Seems like one of those Tupperware-like sealable plastic containers is an obvious possibility. Why do you think that won't work?

I think (but do not know) that those 'Tupperware-like sealable plastic containers' are not going to be as effective at keeping moisture (and bugs?) out. I would think that you would be able to get a better seal with a glass container, and you would be less likely to have air movement with pressure/temperature changes over time.

I was thinking along the same lines as Olin, but given your last comment, I think you want something with a vacuum-seal ability. There are both hard and soft sided (i.e. box or bag) varieties that have valves that hook up to some sort of pump, or some of the bags can be squeezed sealed. Some of the pumps are even hand-operated, no electricity required, ideal for camping.

It would probably be worth investing in one or more moisture absorbers to go in whatever container you choose. Self-indicating silica-based packs are cheap and can be recharged by driving off the water in a warm oven.