If you count the NEMA 23 motors that stick outward, my machine has a footprint of 12 feet long by almost 7 feet wide. The actual cutting size is 50 inches by 11 feet 2 inches.
I'm using Ahrens short and long carriages and his NEMA 23 pinion drives, Gecko G203V driver modules, CNC4PC C11G breakout board, and four Keling 495 oz-in steppers and their 72vdc 20 amp PSU. There is lots of power available.
If you consider using a very heavy gantry with a vertical rail like I am, note that all of the weight is on the upper carriages. The lower carriages bear little or no weight load. So I have ~175 to 189 pounds riding on just two ABEC7 bearings on each side of the X axis. That's ok with me and I'll just have to expect to replace these bearings more often than with the horizontal rail scheme that Ahren recommends. I don't expect to replace them as often with hobby uses. If it were a production machine I would keep plenty of the bearings on hand. Removing a carriage for replacing bearings is not hard.
I would recommend using 3" square box tube for the legs and 1-1/2" x 3" box tube for the other tubing if you can. 3/16" thick tubing walls if this is to be used in a production machine.
The G203V drives can't exceed 80vdc input. 72vdc is pushing it a little but has been fine so far and others are using this. If you want a little more margin at slightly less torque, use a Keling 65vdc PSU. The Gecko documentation on their site can help you determine if the Keling 960 oz-in motors are ok with either of those voltages. I haven't given any consideration to them so far.
The dollars kept me from buying the steel I needed too, but in the end I spent more than enough to correct that issue. Buy what you really want for the table construction. The rest will come in time. While it's fun to build, rebuild, and rebuild again it just wastes time and you'll end up spending much more than you should.
CarveOne
(aka "General Overbuild")
CarveOne
http://www.carveonecncwoodcraft.com