what units out there have easy bypasses like just grounding parking brake wire?

 

just about all of them.
the only ones i've run into with differences are alpine and jensen

 

i just installed a pioneer 4900 dvd and you need to put a seperate switch to fool the headunit into letting it play dvds while moving, so i need to find a double din that this wont happen with for the next customer project i have going, im thinking jvc