I just ran across these auctions this morning:
MCI parts
and
MREs from 1984
The MCIs look like they're in great condition - it's a whole bunch of cans and accessory packs. The guy says in the auction they could be anywhere from WWII (not) to Vietnam (possible) but I'm guessing they're from the mid-to-late 70s just by their appearance.
The MREs also look real good. They have a date packed from 1984.
Unfortunately for me, the guy is located in Spokane, WA, so shipping is too high for me ($30 on each auction) but for anyone else maybe this would be worth a look.
I don't know this guy and I can't vouch for him - I'm just passing on an auction link. If you're interested in buying, be sure to check out his feedback.