I am stoked! This has taken much longer than I hoped (due to me getting distracted) but my sheet metal and HSS parts have arrived:
I have a critical component (drive shaft bearing) on back order, and a few remaining components to order from the US. I have been stalling on those because I want to find a cheaper source than McMaster-Carr for roller chain attachment links. So if anyone has a source for these please let me know. But I will probably start assembling the frame this weekend and see how it goes.