I need to replace my entertainment center

I am also considering a Double Din car stereo but cannot find a way to power 8 speakers or add some kind of speaker selection switch. Have any of you done something like this?

the car stereo head units have connections for 4 speakers on the unit and have rca plug outputs for additional amplifiers on them you could add some small amplifiers for your other speakers and add switches to turn off those added amps off when not needed.
it seams hard to find small amplifiers now though.
possibly some like these? small amplifiers it says 200 watt but really is 2 x 38W RMS