After releasing the Prime’s unlocked bootloader just a while ago, eager developers have released a custom ROM for people to use.
It’s a stock Android 4.0.3 Ice-Cream Sandwich ROM, tweaked and optimized for great performance, overclocked to 1.6GHz. The ROM itself is available on the XDA Developer forum, for those who dare try it out. Meanwhile a lawsuit is in process over the Transformer Prime name, Hasbro vs Asus, the winner will be obvious.