I am looking for storage containers for paricular use in a damp &
smelly basements.  Ideally, it would be:
1) plastic
2) able to be sealed air-tight (maybe using a vacuum)
3) sized in the realm of 2ft high, 2ft wide, 3ft long
4) able to keep air-tight for a period of years

Ultimately, I'd like to store stuff like camping gear, tents, special
childhood items, books, clothing, etc, in the basement for years, and
when I open the container, the stuff shouldn't smell musty or be damp.
 Whole idea:  throw stuff in the box, seal it, open it 3 years later
and have the stuff not smell like a basement.

I've tried using standard Rubbermaid large plastic storage containers,
but they're not air-tight, and don't seal very well.  Also, I don't
want to go through the hassle of using big garbage bags, sucking the
air out and sealing them.  Dehumidifier not an option.

Links to product names, manufacturers, or shops would be great.

Not sure how big you are looking for. Most airtight storage of any
size is done with the large bags that you attach the vacuum to and
suck out the air. Here are a few options I saw

http://www.hangercity.com/ir5galairpet.html
http://www.abcstuff.com/storage.php
http://www.overhall.com/organize_garage.htm  (scroll down a bit)