The Voile Vector BC comes in up to 180cm - if you're seriously going to be schlepping a 75lb expedition pack then your total weight will be somewhere in the 250 lb range. There is also the Charger BC in 191, for even more surface area.
Advantage: No skins needed for low angle terrain. Can use full length wall-to-wall skins if necessary.
Advantage: Is likely to have some float and some glide in fresh snow
Disadvantage: it's a lot of ski to have in heavily wooded or rocky terrain.
Disadvantage: it's not fun at all on crusty or heavily potholed icy (old snow refrozen) terrain, you may as well carry a pair of snowshoes for those days.
Disadvantage: Very much prefers ski-specific (touring with a tech fitting) or telemark boots.
Something like the Altais shown here http://us-store.altaiskis.com/shop/ are going to be *far* more manoeuverable in trees especially if you're not wearing ski-specific boots.
Advantage: Snowshoe-like manoeuverability over rocks and trees
Advantage: zippy fun when not loaded down
Advantage: can be used with the sort of boots and bindings you are talking of. In fact they even sell ones like that.
Disadvantage: Almost no glide at all with a full pack - fresh snow means slogging just like with snowshoes
Disadvantage: icy crust they are a lot less fun than snowshoes
Now, if your skiing will not involve a lot of up and down - I really don't see that in sidecountry off the AT but maybe you're using lowlands to travel then climbing up - then there is a third option. It's called nordic hunting skis. They're hard to find in the US so we don't really need to go there unless you know for a fact that that is what you'd like.
So - what sort of terrain will you be in? Will most of your skiing be done with the pack or without? How much new snow will you have and how much icy crust?
Personally, I'd probably go with the big skis, AT bindings and a set of snowshoes for real ice days but you know your plans best.
Edited by cantunamunch - 3/2/15 at 7:06pm