I'd agree with the cooledor approach if this is just for home storage and you're not trying to class up a room.

If this is for your store -- I wouldn't think a lot of merchants are selling things out of a cooler (maybe bait, pop -- hopefully not the same cooler) -- I think a few guys on here have had good luck with the cabinets from cheaphumidors.com. Not sure how they would hold up for commercial use. I have a small cabinet from cubancrafters.com that I've been pleased with, but it wouldn't work in a retail setting. If you elaborate, I'm sure the fine folks here would be more than happy to provide some additional info.

All that being said -- none of the B&Ms I frequent have well sealed cabinets -- at least not the level of seal I have at home.