Ok, I must admit that I stumbled on this thread late
I am currently working on a project that was going to take quite a lot of power, about 30-40 A at 12 VDC (not anything computer/cooling related, so you TEC junkies can pull your jaws of the floor
). I looked into buiding a PSU, but that was way too expencive, so I went and bought 2 400 W PSUs ($17 per unit). I built a circut to hook them in parallel with, and it can be done!
However, my implimentation of the idea was not entirely successful, as I ordered the wrong parts
I got 9.5 VDC in parallel with both supplys. This was due to having the wrong parts
I would have gotten the full 12 (possibly a little lower, but not significantly), if I'd been more careful in ordering.
I abandoned the idea, though, as the computer PSUs were wasteful (read: power hungry), and took up alot of space. I just ordered the parts to build a 12v supply, which should be more efficent (since I only need the 12 VDC, not all the 5, 3.3, and others a computer PSU puts out).
If the information would be useful to you, I would be happy to attempt testing the theroy further...