I'm keeping an eye on this project. I have an 83 XL600 in my shop just waiting to turn into a retro-motard!
I already have a 17" rear rim that I plan to lace up to the front hub so I have 17 wheels front and rear. Then some dogbones to lower the rear. Clean up the frame. A hand made seat pan/tailpiece with number plate sides. Maybe an under frame muffler. A fuel tank in the shape of an old Elsinore maybe.