Well done. This kind of kit is exactly what a lot of people need and will help them be successful in building their own router. Hopefully you will have other size options in the future, I could see: 12x24, 18x36, 24x48, 48x96 - all usable sizes.

It would also be smart to partner with Gecko and Keling to provide drive/stepper/psu kits that are suited for the router.

The only suggestion/question I have on the design is that the Z axis hangs a long way out from the gantry. There are ways to use Ahren's trucks and still get it more centered over the X axis. One is to have the 1/4" steel plate mounted on the back side of the gantry, opposite from the side the Z axis is on. It's harder to describe than to draw, if you are interested I can put together a crude drawing to give you an idea of what I'm talking about.

Other than that, it looks great!

Gary