If you're in Manhattan, KS, check with Tallgrass. I know they're new, but they may have a few decommissioned kegs laying around. The owner is a friend of a friend, and I've met a few of the brewers a different beer fests. All cool guys. If they don't have any decommissioned ones, maybe they can cut you a decent deal on some.
Thats where I buy my grain from, I'll give em a check.