I'm not an EE (my lack of knowledge will be apparent below) , but I know we've got a bunch of talented people on this board, so I'm thankful for any advice. The company didn't respond to my emails for weeks and the board I'm trying to fix is cheap, so I just ordered a replacement. This is more out of curiosity than need, however it would be neat if the thing could be resurrected, if not -- hey, it'll improve my soldering skills. Here we go:

I got a bunch of development boards from digilentinc.com to expose myself to PLDs. One of them was the XC95 board (Reference Manual, Schematics) with a Xilinx CPLD from the XC9500 family. It did work the very first time I plugged it in, the power LED was lit and even a nice little demo for one of the peripheral boards was loaded. After some fooling around however (erasing and reprogramming the device) I probably made a mistake. For some reason I can't remember making a mistake, a program loaded properly and it worked as I intended it to. The next time I powered the board the CPLD (IC3) and the voltage regulator (IC4) got hot. Too hot to touch actually, plus the board wasn't behaving according to its program. In this state it began to eat PSUs. Power LED went dim, then out. The supplied wallwart didn't output the demanded 6v anymore, but instead 0,3v. Next it killed one of my general purpose PSUs while I tried to erase the chip, but the programmer didn't see the board on boundary scan anyway.
I'm not sure if this is the fault of the last program, as it did seem to work while testing right after the programming session. It wasn't until a Powerdown-Powerup-Cycle that it went mad. Can such a thing be programmed in a way to blow itself up? Do we have unrelated hardware trouble? Right after I plugged in the second (good) PSU, the Power LED(LD1) did not glow. Shouldn't that tell us to take a closer look at the upper left corner, IC4 to be specific? Is there a way to tell with a meter if the voltage regulator is good?

Picture of original board. Nothing looks obviously blown or shorted.