2x4 frame,3 pieces. Box plus 2 triangular uprights/supports. There's a 2x4 on the wall that the supports slide under so it can't fall forward. This picture doesn't show the triangle support or the 2x4 on the base of the wall but should help.
I almost stayed inside the last budget...Considering the idea, I figure I've likely chewed through $20,000 for the room and everything in it. This over 4 years.
Bear in mind the PJ (PT-AE8000), PS4 and the new risers/shelves were free.
This room was started and completed last year (2014).