Help with New audio shop

Me and my friends have been installing car stereo outa my garage since we were freshmen in High School...Now we are at college and we have recently took out a small business loan and bought a place...

It has a Large show room area 2 bay doors and a Nice area we turned into the Office...It also has a dry basement that we converted into 1/2 our lounge and crash area and 1/2 our inventory storage area..This is what we all feel to be a perfect place for a stereo shop...

The problem we are having now is that we want to build a Demo sound room..I cannot find some equipment we need.

1.) A switching board to change between HUs Amps and Speakers Kinda like the thing they have in Wal-Mart But WAY better I have seen digital ones in stores but they are outa business now and I cannot track down Previous owners.

2.) A power supply unit Large enough to hook to the Sound room to run everything.( We have 4 Gell Batteries and a Small Pow Supply right now to run it but its not reliable).

That is all that we can think of right now...Our business is doing great....We are making some real good money...Sticking mainly to car audio and small 12v Accesories but I want to branch out and sell wheels, lighting accesories, baisically Aftermarket car Accesories. We are also building an aditional bay Souly for installing Tint..We are renting that to a guy who has tinted windows in our town ever since we owned a car...

Any info on where this type of equipment can be purchased is greatly appreciated...

Making the World A Louder Place

Great...Thanx...Now if I can find a Good Switching board I will be set...I just dread re-Wiring the whole dang booth...I have some stuff in there now but is all Hard wired systems...I want the ability to mix and match between The HUs Mids-Highs Amps and Subs...I like letting the product sell itself...Seems to be alot easier...

Thanx again for that..

Making the World A Louder Place