On another forum, Bob Frederick (formerly of redletterdodge), has made these annoucements about the 2010 Challenger:

Plum Crazy has been released for ordering! It is available on the R/T Classic and the SRT8. The Classic is planned to have plum stitching in the seats, while the SRT8 will have the plum seat stripe. When ordering the SRT8, you must first select the Plum Grazy Group in order to order the paint. Also, an optional white side stripe is now available on the Plum Crazy R/T Classic. It is the same stripe as the Black one on the Classic, but in White. It is also optional on Black Classics as well. If you are wanting to match up the white stripe with a white interior, Mopar can handle that through Katzkins.

Another great option is the Super Track Pak for R/T models which includes Full-Off ESP Mode like an SRT8 for both automatic and Manual transmission models! It also features 3-season F1 tires, Load-Leveling Performance shocks, Performance brakes, bigger rear sway bar, etc. It does require 20" wheels to be ordered, but if you're getting a Classic they are already there. The option is a reasonable $400, subject to change of course.