Often times, the wife and the HT do not mix well. Wife's like in wall out-of-sight speakers, but those speakers suffer big sound quality drops.
I would suggest putting the M80's on either side of that piece that you have shown. The VP150 could easily fit right above the TV. The M80's look very nice, espcecially if you get a custom finish, and can really just blend in with your home decor.
Good luck!
P.S. the TV could be the only thing in the "cut out" as you were saying. The axioms could be off to either side. Just keep in mind putting speakers inside another tight enclosure will really dampen the sound, so you need to make sure the M80's have at least 6-10 inches all around them. I know of a member on these boards who has put a tower speaker in an enclosure like the one you are considering, but made sure that there was plenty of space around the speaker.
Here is a pic:
You could have the M80's in a large space like that in wall, or simply have them on either side. I suggest having them on either side, but if you really wanted everything recessed, doing something like the picture above would work very well. Keep in mind the M80's are almost two feet deep, so you could probably have 1-2 feet "in the wall" and the rest sticking out a little bit.
