Distributed audio system
Is each room wired for a volume control? If so, you could use 1 or 2 stereo amps to power all of the speakers with impedance matching volume controls in each room. The main limitation of this system is each room is playing the same source, but you only mentioned the laptop as a music source.
A distribution amp system from will cost $1-2k for an amp for 4-6 rooms and about $100 for a keypad in each room. You will also need cat5 wiring to each VC/keypad. With this system you will be able to select a different source in each room.
If the macbook is your source, any remote or keypad would have to interface to that. An apple TV or SqueezeBox3 source could be more easily controlled via an IR or RF remote.