Fred/PlacerLode, just a thought on your rear disc. hub adapter. Not sure if it matters/ if really needed, have you giving any thoughts on adding an outboard bearing? Also, if you need, I have a complete hub assembly(no rim/spokes), including the axle, spacers, brake components and about 12" of the left/right swingarm ends. I bought it off of eBay about a couple of years ago, with the intent of fabbing up exactly what you're planning, using all or as much as possible of the XT250 rear brake components. With (2) full time jobs, I pretty much opt these days to buy bolt on "kits". Anyways, they're all yours(free) if you think you can use them to get this project into production. Let me know and I'll get them sent out your way. All I ask, is that you give me first dibs on two sets
BTW, if you're thinking why only the (2) 12" section of the swingarm ends. Well would have been too expensive to send the whole swing-arm to Hawaii. Figured I could just drill and lag bolt the ends securely into something like (2) pieces of 2 x or 4 x 6-8" or even weld them square, then proceed with the mock up after locating the XT components. Was planning to use the square tubing afterwards to make two 2" extended swingarms.
Anyways, again all yours- just let me know! Mahalo