building a $750 rv system

Hi I'm a newbie here, but see that you have lots of folks who are passionate.  I figured I'd tap ya'll for a little advice.

I just bought a classic 1976 GMC motorhome (The one from the Stripes movie) and I want to put the start of a sweet multimedia system in the unit.  I'd like to spend $750 and here is what I want.  I'm wondering if you were in the same boat, what you would do...

• Unit that can handle two zone video, that way I can pipe a movie to the kids in the back
• iPhone, and Bluetooth capable
• Back up Camera capable
• Great Sound for going down the road!
• The ability for the kids to switch to use a secondary input on the video to go to Playstation (would this be part of the monitors or do I need to consider it now?)
• The ability to switch (at a later date) to maybe remote outdoor speakers, or something like that in the future.
• The $750 doesn't have to include the video monitors, I will buy those later.

Basically, it sounds like I want my RV to be like a pumped out ride.....Can I do something for a reasonable price?  It doesn't have to be audiophile quality, since in reality we aren't actually in the thing all that often.

Thanks any thoughts for the best bang for the buck would be greatly appreciated.

Metrichead!