That is a cool engine. I don't like your chances of finding one in the US. Tomos actually used to produce bikes for Puch, so it is understandable that they would look similar. Plus, companies copy successful models all the time
They were making a 5 speed manual very recently, the bt50. The only one I've seen in the US was the bt50N (the automatic).
You may want to check for more info with the MRA crew. They are all big tomos guys.