I own one of these too. It is an ongoing project. They were specifially designed for Toaster Flyer setups and the isa slots are power and ground only so TBCs and Vectorscopes could be used. They won't work with a bridgeboard. At the moment, I have my Toaster 4000 in it along with a Kitchen Sync, Ycp-100 and the Picasso II and Fastlane z3 I had in my A4000 before I got the highflyer case. I would like to eventually get a Flyer Card and have a full toaster flyer setup. With some of the 2.5" scsi drives available these days, I even think it's possible to run it on a stock 150W A4000 power supply. Mine came with a corroded and nonfuntioning power supply which I gutted and put the A4000 internal drive bay in. Without a Flyer and a 2.5" ide drive I'm going to replace with a CF card , I'm using around 90 watts so I've got around 60 watts left for a Flyer and 3 2.5" scsi drives--another 5-10 watts maybe when I get the CF card in.
http://www.amiga-hardware.com/ has some good photos of the inside.
http://amiga.resource.cx/exp/highflyer has a good description but only has photos of the extender card