haha no not really, china gov't has basically banned 2t and are even taking steps in some areas to round up the remaining 2t scooters and send them to developing countries in africa, etc.
pretty much the only market for these stupid bike engine kits are dumb tweakers who just want some shitty thing to slap on an old huffy, and a handful of weirdos - like some kind of weird cousin of the moped subculture- that really love tuning junky stuff to do way more than it should.
basically the only reason shit ever gets 'better' in china is because of pressure from export buyers, or for internal sale. the 4 strokes have gotten really good because of compaines like SSR and the domestic market have made big investments in improving them. Maybe an importer that actually gives a shit would push for some qc and improvements on one of these motors, but the starting point is so far behind... they are almost like a 50's postwar european design.
There are motors like this, the polini's and the cobra/ morini/minarelli's and stuff, that are made for the kiddie dirt/pocketbike market, that have modern tech and really ripppppp. if you wanted to do a project with something like that, it would make a sensible starting point, they are knocked off like crazy in china, and the companies that import them give a shit about QC because people race them and spend real money on them.
If you want to get weird and build a thing, the lawnmower engine style is definitely the best supported in the aftermarket, cheapest, and i think has a pretty good cool factor because its thumpy and rideable.