My Tablo 4-tuner used to frequently go unresponsive when it got hot (real hot!... during multiple concurrent recordings), but since putting a small desk fan on it, I haven't had a problem since (months). Before the fan, I tried elevating the case, turning it on it's side, etc. I'm a little concerned about leaving an A/C desk fan on 24x7x365 (wasn't designed for that -- fire hazard?).
My question is, has anyone thought about DIY adding a quiet'ish 40mm cooling fan (powered by USB) on top of the Tablo? If you've already done this, can you share your experience and pictures?