When do you plan on arriving? There is a ski swap at the end of October. You might find something there. The prices can be all over the map and it's good to kind of know what you want and what you are willing to pay for it before you get there. There is also a consignment shop, Headwall Sports, that can have some very good deals. All of the ski shops are still selling last years stuff pretty cheap in both new and used. That selection will get more picked over as the season approaches.
As far as a one ski quiver goes, there are many choices and they are all compromises of some sort. I currently like my S7s as a one ski quiver. I have the 188. I like them a lot and find them far more versatile than I expected them to be. I sometimes wish they were stiffer. I also really liked the Armada JJ when I demoed it last year in the 185. I think you should not look at anything less than 95 in the waist and more likely 105 and above for a single ski. I am about your size and currently like skis in the high 170s- low 180s for length. I used to ski very big and long and found I don't need the length as my technique got better. Other people disagree and are still into long large skis. I will usually wait at the bottom for them if I'm in a good mood. Personally I don't like super fat skis. The S7 at 115 is about as fat as I think I would go. Many other people disagree with this. I think fat can be a crutch and super fat is a fad that will swing back in a few years for the non-AK users. Bob Peters doesn't use fat skis. I skied for many years in all conditions without them and spent a good part of last season on a 72 waisted ski to shut up the stuporvisers and trainers who were giving me crap about the "elf slippers".
I may buy a pair of Sultan 94s this season. There is a pair very lightly used that I have had my eye on for a while. I could get them for about $300 w bindings. They would make a pretty solid one ski quiver if you get them before me. I am thinking about selling a few of my skis. I have a pair of 176 Volkl Sumos with Duke bindings and skins that I rarely use. I also have a pair of 176 Volkl Gotomas that I might part with and a pair of 170 Nordica Jet Fuels. I'm just thinking about it and they will likely all still be in my garage when you get here.
One more thing.... You say 40/60 groomed/ungroomed. That will change once you are here and see what this place is about. You will be close to 100% ungroomed and will likely make friends and start skiing OB. There is also great skiing on Teton Pass. I would refrain from buying new gear unless you are getting it on a pro-deal and get something used here. There are lots of skis around. Use the money you save for an avalanche class and some back country gear. You will need a transceiver, probe, shovel, and some sort of decent ski pack to carry your stuff in. If you are in a bind I have several packs that I have never used that I might sell for cheap.
Have a great season! Look me up when you get here. I might be able to point you in a few directions for work, housing, ski partners, gear, ect....