Shopbot is prolly where you want to start looking otherwise you are looking at building your own to save money.
Cncrouterparts.com and Joescnc are good place to start on parts and design.
I would like a big cnc but I don't have the space. I am currently in the process of upgrading my shapeoko to an xcarve with rails large enough to do cabinet sides. I found breaking down the plywood with the TS easy enough until I get a larger shop.