Here's my most recent build.
For the most part I copied the geometry and dimensions of an old school road bike. I added a few touring details as well.
The build process for a bamboo frame has been posted a few times already so I won't add too much of a description, but I'll show you the basic process that I used.
First step after setting up the jig is to miter all the bamboo poles. Apparently I only took pictures of the mitered joints of the front triangle. The stays each have a 1/8" slot cut into one end to fit over the tabs that I welded onto the dropouts.
This shows the front triangle mitered. Also shows the jig I designed. It does the job, but I want to improve it a bit more. The vertical piece of extrusion in the rear and the piece above the frame flex a little too much. To adjust the headtube angle I tighten or loosen the turnbuckle connecting the extrusion to the brake hole in the dummy fork. There's too much play in the turnbuckle for my liking but the error can be mitigated by measuring the headtube angle often when mitering the top tube.
After the frame is tacked I fillet all the joints in the front triangle with thickened epoxy. I used West System's 105 resin with 206 slow hardener and mixed in some 410 microlight and 406 colloidal silica.