Quote Originally Posted by Mario F.
I don't see much of a problem having two PSUs somewhat close together. If the case supports it (I don't anything anything short of a Mid-T will), go ahead.

You just want to make sure you buy top notch material. Don't be greedy. If you have 10 HDs there (god knows why), just make an extra effort and buy 2 good PSUs designed to dissipate as much heat as possible.
For sure a case is a full tower with some room on the bottom to be modified to use 2 PSUs, and of course good ventilation for the HDs. But my main concern is figuring out possible hazards. And finally a little thinking when it comes to turning on both PSUs with the front power button...