You might try cruiser outfitters/cruiserteq, city racer, cruiser bros. and others. If you can track down the part #'s you might see if your local Toyota dealer is competitive.
I could be the rubber lines. It could also be the rod between the master cylinder and power brake booster is not adjusted properly. If it is too long it will put pressure against the m/c piston, so it won't completely release. I would 1st look at the offending brakes rubber line, becuase the...