um... uhh... are you planning on stock switches? or just something to throw together, mount somewhere and have it switch things on and off.

You can wire as much as you want to one switch, just as long as you do not exceed the amperage rating, if that occurs you can add a relay controlled by the switch to handle the high load, but then again, be sure not to exceed the amperage rating of the relay. Also, be sure to protect everything with fuses or circuit breakers.

Switch panels are easy to make... you can use those plastic project boxes from radio shack and mount a few switches in there... I did that in both my dads trucks for his lights and stuff (for plowing and all) and they turned out really nice. You can also make a small plastic or metal panel to mount in place of the ashtray, in the glove box... anywhere you can think of, and mount switches in that... the possibilities are endless.

If you want something made up, let me know... I can come up with something for you if you let me know how you want it to look, where you want to mount it and how many switches/circuits you want.

Gardner Bender (GB)(sold at Lowes and other hardware stores) makes some nice switches, they have rocker switches that are about 3/4" X 1/5" that are really nice for in a car, and can handle a good load.