If you're just looking for a way to route power, search for "power distribution block" and "bus bar." If you're looking for the electronic functions of the motogadget, disregard this and get the twisted throttle unit as the cheapest option, I'd wager...
http://www.wiringproducts.com/contents/en-us/d136_fuse_block_fuse_panel.html and http://www.wiringproducts.com/contents/en-us/d234_power_distribution_blocks.html, for example.
Marine suppliers seem like they have stuff that might work well for motorcycles, especially.
That's the type of thing I'm going to be using in an upcoming re-wire.