I want to build a CNC capable of cutting wood and aluminum (at a very slow feed rate), and the design that I am drawn toward is what I think is considered a CNC router table.

I am considering using supported linear rails for the X, Y, and Z axes. Something like the ones listed here on Ebay:
3 SBR20 400 900 900mm Sets 3 ballscrews RM2005 900 900 400mm BK BF15 | eBay


I'm thinking my machine will basically look like the one shown in this video:
[ame=http://www.youtube.com/watch?v=dwbMh7zXlt8]CNC jogging - YouTube[/ame]

Are there similar builds documented here on CNCZone or elsewhere that I could look at as examples?

Are these types of components---supported linear rails and ball screws--a good choice? Should I be looking at something else for the basis of my machine?

Don't want to ask too much or add too much detail in this first post since there may be a thread or web site out there that I'm not aware of.

Thanks,
Daniel