I race 201s and a 502. All the kits I have had from new I brought in from Hong Kong and Japanese sellers. I have recently been offered some used 201s with lots spares and rebuilt those for the kids. I did notice a 201 in Hobby Co, MacCurthur once.
Good thing is the 201s re pretty tough so they'll be used to their end with kids to learn on. The best places to get TRF cars and parts:
RC Mart, Stella Models, RC Champ and Ebay.
Not too long ago i was thinking of converting over to Associated, for ease of parts and performance. However, the offer of the used kits and bank of spare parts I now have (was the cheaper option instead of new kits) will keep me going for while longer.
A couple of things to note: 1 due to the tanking AUS $$ the kits and parts are getting expensive. When we were level with US $ buying the kits from OS wasn't very painful; 2 as others have said Tamiya is scaling back off road so they are not developing the cars so if you want to do things like run hex wheels, you need to do your own conversions.
All that said, the kits are very high quality and I never had an issue with a build. They also perform on the track if you are willing to spend the time to set them up and experiment and research what others are doing online, as you can't readly get a set up for AUS tracks like say for a B5M - ask Ray Munday etc.
I recently put my 502 in the 4wd Stock A-Main at the Casso Club Series round and finished up 8th. Next Friday I'll be at RC Arena Running a TRF 201XM in 2wd Stock. if you are in Sydney and are still interested in TRF drop by for chat and a look at the cars.