Okay, could swear I've seen this on some builds but couldn't find any pics for reference. Am wanting to do this for my bike and have seen a couple different ways unless I was just dreaming about it. One way was like all mechanical with like a bar connected to a hinge pulling leverage onto another bar and probably lots of hinges in between like near the rear brake pedal alot of little linkages and stuff all chrome too. The other way was just the rear brake cable in a metal housing. can this be done, has it been done or was I just a little too faded one night when I passed out and dreamt the whole thing?

One of the Cafe' builds put a hinge on the swing arm - he used the passenger peg hole as the pivot point...not sure which build.  This change is necessary on a Cafe as the pegs and brake pedal are moved back to the backside of the engine.

The GT 380 and 550 bikes used a cable rear brake that had the outer sheath mounted to the rear brake drum......it might be possible to adapt that system if you find a looooong cable to reach the brake pedal at the front of the bike.

The cable is in a housing until about halfway back.Then it's just exposed to the brake arm.