I can certainly recommend Axiom's speakers for your room size and aesthetic concerns. The M60 towers may actually be a better choice for you. They are easier to drive, sound identical (except for max volume output) to the M80 towers and while your room is Large, it is not Massive and the M60 towers should be able to handle that room size just fine.
Basically, if you are using a dedicated amp, then the M80 Towers may be a better choice. But since you're powering them with a receiver, I would nudge you towards the M60 towers. Even though the Z7 is a flagship receiver, it doesn't have limitless power reserves and it will have tighter control over the slightly less demanding M60 towers
The upgraded Vinyl finish is also a great suggestion! Doesn't have to be real wood to look great and it keeps the bottom line lower!
Finally, Axiom's subwoofers are expensive! I would suggest that you could save on the sub by purchasing from a different subwoofer manufacturer. SVSound or HSU, for example have subwoofer that I would easily put toe-to-toe with the big Axiom subs, but for lower prices that may help you stay within budget.