I don't think I've ever played any of the Riders games.
Speaking of Sonic racing games though, S&SASR (I'm not typing that all out, haha) was pretty good; at least for the DS it was, since that's the one I bought.
I don't think it'd be in very good tastes to have the Rabbids in that game.
Oh, and here's the full list of character skins in the game (From a message on Gamefaqs):
Rayman
Globox Rayman
Globox
Red Globox
Teensy Ray
Teensy Globox
Generic Green Teensy
Goth Teensy
Princess Teensy
Wizard Teensy
King Teensy
Ninja Teensy
Teensy who lets you get Treasure
First Grand Minimus Teensy
Undead/Zombie Rayman
Undead/Zombie Globox