NSW Railcars. RM38 Creamy Kate. Kits were/are? available.
X100 & X200
7201 Was always only a test bed for what eventually became the 73cl, while not an overly great success on general trip working it actually found its place as a successful shunting engine on the old Balmain coal loader, taking the place of a standard goods engine on the actual unloading #1 Balmain shift, like many other experimental items it had its quirky nature but as the amount of drivers who were qualified for it, got used to it, it did a good job, my regular mate at the time was one of them & never had issues with it.
Stephen Johnson Models made a "Creamy Kate" kit......
There have been 2 paybus kits that I know of. One was the early type with the single end (had to be turned at terminus). I can remember as a kid in the late 50s, seeing one of these come to Narrandera regularly. It required a NWSL "SPUD"....I sold my model when I went to DCC because I couldn't ever imagine being able to convert it to DCC. Not sure who made the kit....it was a resin casting from memory.
The other was the larger type with a cab at each end. I think it was made by the same mob that made the older/smaller paybus.
Bergs made a white-metal X200 kit at one stage. Not sure if anybody has done the X100 though.
I don't think any of these are currently available....probably ebay would be your only hope....they seem to crop up from time to time.
I don't know anything about 7201; sorry mate.