very nice pictures! nice to see whats going on.

I can tell u that cgminer works charming with all my boards (running since yesterday. Ill post a pic)

So it looks like the bottom heatsink and fan is definitely helping with the speed/thermals.  I am going to give it a test.  

Does anybody know if the heatsink has to be suspended in air?  I am putting these babies on top of a wooden rack.  I was thinking of supporting the middle with another screw since I have noticed the board (quads) to flex a little bit.  Now I am thinking of covering the bottom with a piece of thermal pad that is supported by a heatsink (I have ~20 old 1U socket 478 Cu heatsinks).  I assume that as long as the pad/case is non-conductive/capacitive I should be alright. But please let me know if this wouldn't work before I experiment.  (@pazor:  Your setup is definitely more elegant.  But I have a number of boards and the cost with the screws/added heatsinks is a consideration.)

FPGA
pad (fasten to the board via the 4 standoff screws, maybe the Fujipoly thermal pad, frozencpu dot com)
heatsink (same height as the 4 raised standoffs)
Wood

The alternative is to use 4 passive VGA coolers attached to the bottom of the LX150.  Probably safer and cleaner.

Interesting thought to put a heatsink on the bottom.  Maybe I will experiment with it as well.  
@pazor:  What speeds are you getting without the bottom heatsink?

CACoins reported 228 MHz (224 to 228 MH/s) in the hardware thread.

I have seen 224 MHz (about 223 MH/s) on a single.

The speed of the bitstreams for Singles and Quads are the same. There are only some differences in the glue logic. Routing of the rest is the same. On the Quads I have seen 240 MHz (239 MH/s) with a FPGA's from a lucky lot.