Need help.

My project goal.

Be able to cut up 1/2" pine, and up to 1/4" plywood.
Size, about 20" X 48"

This is where it gets fun, i'm not sure where to start. I checked
out my web sites, and have a good idea of the componets involved. I
was thinking about using a roto zip, or similiar tool for the
cutting unit. I have some idea's on the basic mechanics. But not
sure what i'll need in the line of stepper motor size? What cutting
speeds will i be able to atttain? And the big one, cost... I have
acess to all the tools that would be needed to build a project like
this, just need some direction.

Any help would be greatly appreciated.