Mate - You have already committed to the restore the moment you bought the backglass ! What you need is a bit of patience, as you may find a head or body on eBay etc. I've seen wedgeheads (just the head) and I picked up a Far Out lower cabinet a few years ago (currently stripped and ready to be repainted as a Pro Football).

Even if you could borrow the head and or lower body from someone to fabricate from scratch - that would be a start.