Ok, I'm totally up and running now as you can see here:
https://i.imgur.com/n3Vs1Xx.jpgOverall, I think it was probably a driver version, I wiped all the 12.5 drivers I was using and went with 11.12 clean install and the BSODs mostly stopped. Here is a top down view that shows all the extenders and the types I ended up using.
https://i.imgur.com/RkScIqm.jpgIf I number the slots from left to right in this picture as 1234567, the first thing I tried was 1x riser ONLY in every slot. The 1x riser did not work in slots 1 and 3 (both 16x slots) alone, I know others said they got it to work with this mobo, but I could not. I did not try presence pins, that was going to be a last resort tactic only.
I was able to make 1x risers work in every other slot though, including the 16x slot closest to the CPU (#6 in the picture above).
So that meant I only had to get the 16x risers to work. I tried the same card in both slots 1 and 3 with the 16x riser, and for some reason it would only work in slot 3, the device manager/cgminer/GPU-Z did not even see the card when installed in slot 1, even when there were only 2 other cards installed in the system, so I don't know if I got a bum slot there or what, I know the GPU and riser worked, because they worked in slot 3.
Anyway, I met my objective, 6 cards/8GPU all working. I ended up using 5 1x-16x risers and 1 16x-16x riser. As you can see the length was really important for the cards that were plugged in farthest from the board, I was at the very edge of the possible even with the 30cm hashrate connectors.
I'm pretty sure I don't need all of these to be powered, but I couldn't find any unpowered risers that were long enough, and all of the hashrate store risers were plenty long so it didn't matter.
I do think that the molex connectors are a pain to hook up, I wish there were some way to make that connection a little easier, you have to fidgit with it for some time, then you have to worry about getting the next molex in (power supply ports are a premium in these rigs) and then making every thing fit and not get tangled.
But overall, I'm very happy and now I have a pattern for how to do my 2nd 5xxx rig, which is going to go on the other side of this same box...just in time for the winter.
Oh in case you were curious, cards left to right were slot 2: MSI 5870, slot 3: ATI 5870, slot 4: ATI 5970, slot 5: ATI 5970, slot 6: HIS 5850, slot 7: ATI 5870. For some reason the MSI 5870 runs about 5C hotter than the ATI and gets ~400kH instead of ~420 like the ATI 5870, all the 5870 have 1600 shaders so I'm not really sure why, also that order doesn't match the cgminer order, which I'm sure you can figure out knowing the cards like you all do.