Building an IMSAI (or a TIMSAI, for that matter) is straightforward, but not something you do just on the spur of the moment. There's many days of work in laying out the PC boards (it would certainly have helped if I had a PC-board-specific CAD system when I was laying out the front panel and motherboard of the TIMSAI!) and a substantial amount of sheet metal work in cutting, punching, and bending the chassis parts and the cover. I wouldn't have even considered the project had I not had access to professional PC-board etching facilities and a fully equipped sheet metal shop.