You might also look at the ACT Desktop Machining Center III. It has a working area about 12" x 8" and it can cut steel, although it won't do very heavy cuts. It's a fairly heavy machine for its size at over 200 lbs, and it uses ball screws and square profile linear rails. It comes ready to run (even the computer is included) so you can start making your parts right away, rather than get bogged down in a retrofitting process.