You could also consider making your own printer, for $1500 you could quite easily make a large scale (500mm+) enclosed cube printer with a solid aluminium extrusion frame. Might be the cheapest route as there isn't much in the large format consumer market and it's definitely the best way to get it exactly to spec with what you want. That being said, it's a bit more work, but there are designs out there you can use and I'm sure people (including myself) would be happy to help you with the design process if you choose that route.