Thanks to eveyone who has replied so far. As I see it, it's much better to have a design like the Creality Ender 5 which uses a motor for the Y axis and another motor for the X axis. Of course, the X axis will rrquire a motor on either side and two belts.
As for the heated bed, most people have reccommended silicone heaters, which seem like a good idea. I was alternately considering getting two MeanWell PSUs and having a grid of four heated beds with two beds and a nozzle heater hooked up to each unit. I'm not sure if even MeanWell can handle that though, so the silicone heaters are probably a better idea.
Also, whatever build sheet I use will have to be attatched to a rigid surface to avoid flexing during thermal expansion.