What're some solutions for selectable multi-room (4-6) Wireless Speaker set-ups?

Dad recently fully renovated and now wants the home audibly infused. Doesn't care for the in-wall solution, just wants a couple speakers hidden in corners plugged into a wall.

Nothing too thunderous., just solid decent sound. Doesn't need a home theatre component to that, but I'm sure could be swayed hehe.

Is there such a receiver that will connect a 12-20 speakers wirelessly with decent range throughout a home?

Being able to select which rooms are turned on is a requirement.

Now I'm curious., with wireless speakers, are they powered on constantly or can you find ones with a remote that will allow you to remotely turn them on/off? That would be ideal.

He's old school (no surprise) so frankly, if he see Bose offering anything in their line, he might be buying that.

I've seen airplay speakers? Could we potentially connect multiple airplay speakers with one iOS device? Not really a preferred option, but I told him he could just get a radio app and listen to the radio through his iphone. Doesn't want a dedicated iphone/ipod connected, or have to connect his iphone while listening. Rather it just be a receiver.