I'm with you bro. I made my own out of 1" angle for the base, put a piece of 2"x1/8 flat across the bottom for support and 1"x1/8 around the middle to keep the batteries in and to hold the solenoid. I used the stock holes in the fire wall and the stock supports under the batteries for support and haven't had any problems. It might have cost $10, but I doubt it. As far as the dimensions are, I just took the 2 batteries and laid them out like I wanted them mounted, took some measurements and built the tray. Email me and I'll send you some pics. Hamy.
One Way Up Racing