No, for road use, you don't need a bias bar with 2 master-cylinder: the donor M/C is enough, and easy to set up with the 2 front outlet and one rear outlet. If you use rear discs, you will need to use the donor proportioning valve though. I wouldn't go the dual master-cylinder way if it is for road use only.
However, if you really want a brake bias balance bar with 2 Master-Cylinders, you can buy just the bias balance bar (Rally Design for example) and weld it on your pedal shaft. But you can also buy an already made Pedal Box with balance bar (and even M/C, and reservoirs): OBP is selling very neat ones that fit narrow foot wells of kit cars:
http://www.obpltd.com/obp-shop/race-...it-car-special
They are not cheap, but for having seeing some as we sell them in France, I can assure it is very good construction.
You can also have a look at this thread, the pedal box I made could be adapted to use a balance bar and dual master cylinder, even though you're gonna need to make some adaptations (space between pedals, running the balance bar adjusting cable, and so on)
http://www.haynes.co.uk/forums/showthread.php?t=8143
Hope this will help. Good luck for your built
