With regard to blending of bikes---in the early days "blending" was commonplace. The first world title was won on a 7R AJS 350cc road race engine enlarged to 500 with BSA parts in a BSA based frame with Norton Roadholder [I think] forks. Nearly all the Hedlund, Monark, Lito, Husky etc were hybrids. Tribsas were the poor man's [or innovators] alternative to the expensive Goldstar, and led on to the Metisse. Forward to the 70s and on to the current vintage movement and take away the blends, [Metisse, Cheney, Hindle, C&J etc, then remove the japanese powered Maico, CZ, Husky chassis specials etc and you take a huge chunk out of our fields.
It's great to see correct, original production bikes, but there's a place for both.