Switch source

[Zephod_beeblebrox2]

I'm hunting in vain for a SPTT switch. Has anybody any ideas where to get one? Its the toggle switch that controls my wipers - off, lo, hi or off on on. Mine is broken - its a bitch to get the damn wipers to turn off once they're on!

[Roadrunner]

Go to ebay and search for 3 position 12v toggle switch.

[somewhereinusa]

Center off DPDT switches are quite common.
Here's just the first search I did.

Amazon.com: Heavy Duty Toggle Switch DPDT Center Off 20 Amp: Automotive

Off On On not so much, I don't see any reason On Off On would work for you application.

[taskswap]

If you want the aircraft look you can also try here:
B&C Specialty Products - Switches

Used them a lot for the plane. They have every combination you can imagine. It looks like a short list but it's because the first page is just the number of poles. If you click single or double pole then you can choose any combination of off/on/momentary you want.

I've also had really good luck with these guys, who carry a lot of the weird stuff you sometimes want in automotive work, like weather-tight power connectors, etc:
Toggle Switches | Automotive & Marine Toggle Switches | Waytek, Inc - Page 1 of 6

And if you're on a budget, keep your eye on these guys:
Switches - Toggle | All Electronics Corp.

All Electronics, AllTronics, and a few other electronics shops have all sorts of funky things. If you like lighted or oddly-shaped switches, they're a good place to look.