I got a bunch sitting in a box if you want replacements. Though really you'd be better off with upgrades. They're a pretty standard 50mm fan. I think someone around here probably posted a listing for better ones than stock.
I tried searching the hardware forum for r808 fan and the only post that came up was your OP on the r808. If anyone still has that listing for the upgrade, please let me know. If not I could buy the ones you have sitting in the box, it doesn't matter too much since I plan on giving it away anyway.