While they aren't (necessarily) multi-day expeditions, the Adirondack High Peaks offer a significant winter challenge to anyone, and I know of a few folks who've used to tune up for Himilayan expeditions. Summitting Marcy or Algonquin in winter can be quite a challenge – I've been turned back in whiteout conditions on the latter.
Check out this forum that is focused on climbing the 46 highest peaks in the ADKs, which are now focused on doing so in winter conditions.
http://www.adkhighpeaks.com/forums/