Ive heard of people wrapping towels around ice packs and placing that on top of their humi. I just dont think thats a practical long term solution. Like Darb said your best bet would be a wine cooler.
also you may want to try moving down to the floor, as they say, Hot air rises. its worth a shot.
I keep them in their original boxes to contain any possible outbreak of those little boogers that sang "She loves you, yeah, yeah"/