High print area printers aren't really what I'm interested in because of tremendous warp issues even when printing with PLA. Around the 25x25mm mark you must be using magic to keep the print stuck to the surface. The height of the print however can be much more, which is why almost all printer manufacturers concentrate on that. I also know that I probably could have spent less by just buying a 3D printer, but for me it's more about the challenge of designing and building one from the ground up.
If you're interested in a high print area, you could buy a cheap cnc from China and replace the mill with an extruder. That should be really easy :)
RE: Building my new 3D PRINTER - Intro