For the frame I used 'Plumbers Strap' and rivets. Along with super glue to hold wires and the photodiodes in place. I used double sided sticky foam tape to fasten the toothbrush heads and the motors. The 'eyes' are subminature panel mount red led's from Radio Hack. The actual eyes are large area photodiodes from goldmine electronics. The motors were scavenged from cell phones.
I have found you don't need a special toothbrush to achieve forward motion, just take regular toothbrushes and bend the bristles back and set a book on it for a while. These toothbrushes were the 6 for a dollar type. The battery fastener is one of those hook and loop (Velcro) cable straps for your computer cables. It worked out great.