Personally, I actually don't see the issue with a cup being entirely rainbow roads when it comes to naming conventions. Take for instance RR MKWii, RR MK7, RR GBA, and RR DD are all released for booster pack 4. We can then put something like...
b4RRw
b4RR7
b4RRg
b4RRd
Of course, these acronyms...