I stumbled upon this thread kind of late. I appreciate the links that were supplied. I noticed that nobody provided any links to bellows construction. So, here's my feeble attempt to add value to this thread with the research I've already done on the matter, below. By the way, I've been planning to make a bellows enabled pinhole camera, so that I can go from wide angle to normal with the same camera by adjusting the pinhole's distance from the film plane. So for that reason I have these bellows links:

this one is, I believe, the best one for making square bellows with nicely formed corners/edges

this one is good for tapered bellows you can also find other pages on his site which are about camera making, pinhole camera making, etc. this guy is like a MacGuyver. maybe not the best looking, but surely a scrappy guy who can show you how to make something useful, which is afterall the most important factor eh?

this is a link to a page listing all the known camera builders on the internet I've had a look around on some of the pages. there are hours and hours of web-surfing off of that page.

specific instructions with photographs in a PDF file you can download for making Isolette bellows (for that old folder). same guy but here's a 4 x 5 camera he made with rudimentary tools and supplies. again, looks are secondary...

I hope these links are useful for some. I'm setting about to make square bellows with the nice corners. Just got all my supplies in order today. I couldn't find blackout fabric in black. Rather it was white, intended for use behind draperies. That's alright, I'm going to spray paint the inside fabric with matte black paint, which I also got. I'll leave the exterior in white. I just have to work out the details on the dimensions (accounting for the film back size particulars) and a way to steady the front and back boards so that it can be locked down with no movement. Once I get the dimensions part worked out, then I'll start on the bellows.