Yes, ad an EBB or sliding dropout to one of those elevated chainstay things,
and It would be simpler..

even like the Alpine Stars frames, they only elevated the drive-side ..

and yes S and S machine shop does make small diameter connectors.
there are several other ways people have managed the split.


personally I would like to see a covered drive train, in the Dutch tradition,
one of stretched truck tarp on a wire frame.
covering the Belt drive,
since they still would eat trouser legs, so covering them fixes that .

and a covered chain drive, out of sight out of mind, rarely gets oiled.

If the Belt drive were hidden It could be ignored , to no problem.

but its still in the gee whiz look at what I did stage now

maybe as a mature technology the practical will begin to adopt the parts.