I plan on removing the metal plate from the back too. It does not appear to act as a heat sink. The project will contain the printer, so there's no worry of exposed circuits on the box itself. The plate weighs a lot, and I'm trying to keep the weight down.
I note that there's a lot of open space on either side of the printing mechanism. if I relocate the LED and button, I could cut things down a lot more than I had planned. I'll take photos.