I found a useful link for those who might need to know what kind of trace width is required on PCBs to carry a given load. If using BatchPCB to have your design fabricated, use 1 oz/ft^2 for thickness.

http://www.circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/

Thanks Eric, that will be useful when I am actually ready to make a PCB. I saw you are selling a couple of your designs on the the site but I didn't understand it very well. Are you selling only the design, or a PCB, directions, components, or all of the above?

The way they price the designs for sale at Batch PCB: the sale price includes the PCB fabrication cost and any profit for the designer. I've put my designs up for sale at about a 5% mark up over the fab cost - I'm not going to be rich from the royalties any time soon. If you want any of the designs, I'll give them to you with schematics and board layout, but they are pretty function specific.
They are PCB's that I intend to use for my vehicle project (a 3 wheel, tilting, drive by wire motorcycle). I've already tested out the basic functionality on a low speed, un-powered design using breadboards; As I plan on building a powered and much faster design I didn't want to have some failure because a wire came loose, so I'm trying to get most of the electronics put together on a PCB. The dual 328p circuit is the heart of the project - one chip takes the input from a wii motion plus module and nunchuck and outputs to steer (using counter steer to balance). The other 328 is mainly for running the display. I've been using big RC servos to steer, but those are underpowered, so I'm going to incorporate my own motor controller and 12v actuators (hence the H-bridge on the PCB too). The other PCB design is just a small circuit for a Hall switch, which I'm using in conjunction with a few mag pickups on the wheel to calculate RPM and speed. That feeds back to the main 328 as well.