I finally found a suitable case for the Adventure. This is is it. An Antec Skeleton. In this shot you can see the Adventure 2800 with the power supply underneath.
This is the supporting bar that the back plane of the cards screw into. The black mark I have drawn is where I need to cut it to accomodate the PCIe bridge card. This is in about the 11th slot if one had a normal motherboard.
And here it is again plugged into one of the Asus P6T's. I only have two of these left after recent upgrades to Asus P8Z77 motherboards. The short green card just below the fan is the other PCIe bridge card.
In this picture I am looking down on the Skeleton. You can see the 4 graphics cards starting from the left. You can also see the clear plastic supporting bar across the top.
Another shot, which looks a bit clearer, where you can see the graphics cards.
At the moment I have 4 of the GTS450SP cards installed in it. These may not be its final configuration but they will do for now. Indeed it might not be driven by a P6T even. I am looking at getting another P8Z77 to drive it.
I have run some Seti and Einstein work on it since installation. I had some issues with the Einstein GPU tasks erroring out when running 2 per card. I reduced them to 1 per card and they appear to be working fine now although it needs some further testing. Seti tasks seemed to run fine (using the x41z app from Jason) running 2 at a time.