Thanks so much for all your help, guys.
I do have the wheels and carbs.
Actually, it all started with a frame. I have been looking for a good CB400F project for about a year and a half. None of the three good projects I saw had papers and the DMV regs for registering paperless vehicles have really gotten tight here in Quebec. It is in fact impossible to register a bike/car if the last known owner doesn't sign it over to you. That goes for all cars, whether it be a 1999 Civic or a barn-find 1963 Ferrari GTO. And it's your job to find that owner, not the DMV's. (Ask me how angry I got when talking to the rep on the phone).
Anyway, I found a '77 frame with papers for 20$ a few months ago (guy had a "rebuilt" carb pack for 40$ too!) and I started looking for a decent project. The one I found was cheap and was in great shape. Sadly for me, the frame without papers I got is in much greater shape than my frame with papers. The 3 biggest things I'm missing are a tank, seat and complete exhaust. I know a repop seat can be had for not much money, but the tank and exhaust will surely set me back several hundred dollars.
As far as I can tell from the PO, he bought two bikes in order to make one good bobber show bike and kept the better bits for himself. So far, all the brightwork is really shiny, the clocks work great (with my drill, mind you) and I have two harnesses so I can surely make one good one out of the two if I need to. My biggest concern is the motor. It turns over really easily with the kickstarter and I was told the compression was good, but I have not tested it myself. I have no real reason for concern, however.
And the reason for the six rear shocks is that I got a crusty set with my frame, and two sets with my parts lot because the seller will surely go for some upgrades for his bobber project.
I'll go with the rolling chassis suggestion for now. It seems like a good way to start. In any event, these bikes are pretty easy to assemble - if you have all the parts. I tore down my 2nd CB400F twice and it wasn't too bad... Although I'm sure I'm remembering that wrong!