Fortunately I can do some prototyping at school without having to pay for anything. Once I get a final design, I can't imagine it would cost too much. Adding the bits and pieces to the PCB is going to be the hardest part.Assuming we can all agree to a form factor, I think a group pcb fab buy wouldn't cost too much per person. I personally was thinking in terms of single adapters, if you keep the adapter pcb small and light, the locking mechanism on the pci-e slot should be enough to keep it stable. Then, as long as the card is properly mounted to the case there won't be any issue.