With all the other assorted pieces of techno-wizardry in these expensive cars, I wouldn't think it would be a big deal for them to keep a manually operated parking brake but maybe electronically assist it a bit to compensate for the weight of the vehicle. Would probably be a much better solution for all and might not cost any more than the current electronic parking brake does.

I mean, these are driver's cars after all -- the current parking brake belongs in a Lexus.