As he mentioned, I have a lot of video around here. At the end of last season I compiled it all [by season] and transferred it to Vimeo. You can probably immediately see the progression from 2006 until mid-2009. I have some late 2009 stuff that shows more improvement, so if you (J3rry, or anyone else) want that, just shoot me a PM with an email address I can send the clips to.
I think that this thread has gotten a bit confusing in that while assigning names and definitions to all these transition types might be useful to some from a coaching aspect, and a skier should be able to "do" any of them, they are never going to say while skiing: "okay, I'm going to make 10 turns on this pitch with two cross-overs, three cross-throughs, a cross-under, a cross-over because the previous cross-under will put me in the back seat, a cross through, and a final cross over because I'll be tired from making 9 turns already. You get the idea. No one does this unless it is a drill.
I haven't studied J3rry's video much (watched it twice), but in reading some of the comments I think you guys have hit on a lot of what will help, including the leaning in and rotating in, weight on the inside ski, hands (inside) dropping, lack of lateral balancing movements, following the skis a lot, not a lot of "true" sidecut use, use of mostly one transition type (accept in the SL clips, I didn't see anyone pick that up yet, but I may have missed it), some back-seat habits, etc... Those aren't just little things to work on; they take a lot of drills, a lot of attention to movement patterns, and changing the skiing significantly to something that includes higher level movement patterns. Its hard work too.
So... J3rry - here is your MA:
So what to do & why (perhaps over-simplified of course; if you need more clarification just let me know):
Stance & putting your skis on edge... Garlands on flat terrain (a lot of work can be done with garlands; never underestimate their usefulness) that work on developing a very natural stance and rolling on and off the edges without using leaning in with the upper body in order to put the skis on edge. Tip from the feet. You should be able to roll onto edge standing still and while moving. If you find yourself displacing your upper body in order to put your skis on edge you are starting the movement incorrectly. It starts at the feet.
Flexing & extending... Work on getting flexing and extending in the transition; flexed through transition and extending into the turn. This will help (among other things) your ability to put the skis on edge [engaged] very early in the turn as well as your ability to handle variable terrain. Boot touches [hands to boot cuffs] in transition will work to help this out; do them without breaking at the waist a lot. If you have a terrain park with small rollers in it available to you - ski through the rollers without your body from the waist up moving up and down. When you have that one mastered, link turns through those rollers, putting the transition on the rollers and the turn in the trough. If you get much speed you'll know when you get the timing wrong... Remember that just because you're tipping to edge early with this new movement pattern, it does not mean that you are pushing against the outside ski to get pressure. Just the opposite in fact. The pressure will come on it's own - you are just extending your outside leg into the turn to allow that pressure to come to you as the turn develops. Do not push on or off the outside ski because the only thing it will do is push your center of mass inside the turn too far - putting you on your inside ski, which is something you're trying to prevent.
Staying forward... think of staying forward like this: Put your feet behind you. Instead of trying to push your upper body forward, push/pull your feet behind you. You can practice this stationary by simply doing what I just said above. Also try it in transition while executing your garlands on flatter terrain. Transition is a good place to make sure your skis aren't running out in front of you, but the process never stops, especially with the inside ski - never let it get out in front of you and always be pulling it back and up (as you gain higher angles).
Upper body (a lot can be done here)... Your upper body range of motion (or at least what you're using of it) is really lacking. I've found in my own skiing that its one of those things you can lose fast [or never get] if you aren't working on it all the time. The better your skiing gets, the more you will have to be conscious of what your upper body is doing. So your body can move in three planes (fore/aft, side-to-side, and rotationally). I covered fore/aft so I'll focus on the rotational and lateral movements. For the sake of argument prevention lets call these movements angulation (lateral) and counter (rotational). These are not positions, they are movements that you move into more as the turn progresses (generally speaking). If anyone ever teaches them to you as positions ski away from them (chances are they won't be able to catch you if they teach like that anyway ). Angulation is used for lateral balance (so you don't tip over and so you can maintain pressure on the outside ski when you need it - note you may not always need it). Rotational counter also aides in allowing for even more extreme angulation and will make sure that in your turn [especially post fall line] you aren't facing across the hill or into the hill. Rather from the pelvis up (where both of these movements originate), you will be headed toward your next turn. A good angulation drill is where you stretch an arm out to your side and break at the pelvis during the turn and touch your boot cuff (outside hand touches the outside cuff). Another is eliminating your pole swing and dragging the outside pole (press the basket into the snow). A good countering drill is one that many race coaches will use where you strap both of your poles around your hips so you can see where your pelvis is facing. You can then use your hands to direct your pelvis in the direction you'd like to go. Another is to select a fixed point downhill from you and ski toward that point without ever facing your upper body away from it. This does the same thing as the poles drill, but it lacks the instant feedback that the poles drill has.
Hands & pole swing... Your hands are also all over the place. Try to isolate your pole swing to a swing with your wrist and a tap. Dropping the inside hand will likely negate any improvements made from the information above, so even though this is a small point, it has major repercussions in your skiing. The best advice for fixing your pole plants that I can give you is to eliminate them entirely (keep the hands out in front of you without a pole tap, swing, or dropping your hands; keep the poles though). Once you can ski without the plants, put them back in with just a simple swing from the wrist and a light tap.
Overall, you're a very good skier. The advice I have given you is based largely on my own skiing and own experience while developing my skiing over the past few seasons (based on deficiencies that I was able to identify or have identified by others). As with probably everyone else on this site, I am constantly working on improving and it is a continuous process. I've gotten a lot of good advice over the years and been fortunate to have several people who have taken a strong interest in helping me develop as a skier, so hopefully you can get that as well. Good luck. Let me know if you have any questions.