Perhaps I shouldn't post this here because it's a link to an auction, but I have no connection to him nor am I trying to help him in any way.
But here is a good looking table. Granted, it's probably too flimsy to be very accurate because it uses TSlots and doesn't even have angled braces, and the motors are very tiny, and the Tslots alone probably cost $2000. But still, it has a nice look to it!
I have no idea why more people arn't using the raised sides for the gantry support. It simplifies everything and the only thing you loose is the ability to load from the side.
Also, the rack-and-pinion drive on both the X and Y seems much better when the size of the machine reaches 4x8.
To me it seems that the above table would be almost perfect if the frame members had angled braces and the metal were something a little more stout. I know people here like to use aluminum because it's easy to machine. But still, if you had a metal that was very hard and didn't flex, could be machined precisely, and had good temperature characteristics I think the above design would work well. The design is a sort of "Minimalist design" using only what is needed with as few parts as possible. So even if it were very hard to machine (or have machined) the parts at least there would be few of them. Light steel?
Any thoughts?