I was not content with the 20"x40" cutting area of my first CNC router. It was a great experience build it from the book, but I want to be able to cut much larger pieces of wood, to design much larger things. Since standard sheets of wood from the builder's supply are 4'x8', I figured that was the perfect size machine. Luckily, Patrick Hood-Daniel sells kits for large machines over on his website, BuildYourCNC.com.
Patrick is currently shipping his 4th generation machines, that he codenamed BlackFoot. (I was curious about the naming too, and he said that he lets his young kids name them.) These new machines feature improved roller chain drive, a single motor drive on the x-axis via axle, adjustable bearings, redesigned vacuum holder, and aesthetically pleasing design.
The BlackFoot 4'x8' kit costs $2405.00, without electronics. Luckily, I was able to use my same electronics purchased for my smaller machine. I did, however, have to build a table, as that is not part of the kit. I will have to get a new, bigger, router though.