Cool idea to convert the CW, I should have thought of that... I bought mine last fall, got hooked but wanted more.
So I built this...
http://www.youtube.com/watch?v=TMy-rsPafdo
I am just in the "firing up" stage right now but so far, so good. Belt driven(3:1 gear reduction gives resolution of about .0003"), 4' x 8' x 8" cut area, safe cuts(.250) in MDF at 120imp, 400ipm rapid, and so far I have been getting repeatability measurements of less than .001".
I'm keeping the CW though because it has its advantages too - quick 3D carves, the designer software, self setup, compact, etc...
Plus, why not have double the fun!