Sorry... but if I am to take what you are telling me the customer is saying at 100% face value - then the customer is f^n stupid!
You are telling me that a keypad in the wall (that they can't see the wires to anyway), makes a difference to them if it communicates back on a wire in the wall or wirelessly. BS!
Get the iPort mini kit ($299). Put a iPad Mini in it ($249). Then show them the custom touchpad you are installing in the wall is wired "See". They don't need to know more than that.
Tell them you can upgrade the device latter with icons to control lighting, HVAC, CCTV, and other cool things too. SONOS for the win.

[edit]: Just looked up the prices = You can do an iTouch for $199. And Vidabox has a solution for $149 that is surface mount over a single or dual gang box (only 1/2" coming off the wall). Just use a POE switch or POE injector. $350 per room - but since there is very little markup I would charge at least $450 or more for that solution (that just the parts).