Gary-
First let me say that is a great looking layout - very detailed. As for price, it depends on your market and if you are doing it partly as a favor for a friend and not for a living.
I think I would be looking for something closer to twice what you quoted. The ent wall here is priced the same as yours, for a close relative, in Westchester county NY, and is being delivered and setup unfinished (primed) to be finished painted in white by their painter.

- Pop-up TV Wall Assy ver3.jpg (19.21 KiB) Viewed 14762 times
The TV pops up from the center cabinet.
The doors/drawers are in wood only to show the detail.
A thought - is the TV accessible for service ? Looks like it's pretty thoroughly closed in.
Otherwise, again, a very nice job. What are you making it out of, and finishing ?
Joe