Your best bet is to go (I know, shudder!)... British. Find the associated parts from, say, a Spitfire, MGB, Spridget, Mini, etc. Then, just use good quality wiring to hook it up, to avoid the "Prince of Darkness" specter.
Okay, this is a little hard to explain, but I'll give it a try....the British wiper system consists of a 2-speed-with-park motor, with a cable box attached, which drives an inner cable in & out. The outer cable is simply steel brake line, which you can shape to whatever you want, and can be as long or as short as you want. To drive each wiper, there is a "wheelbox" bolted inside the scuttle. As the inner cable goes by, through the wheelbox, it drives a gear inside the wheelbox, turning the wiper arm shaft. Then the cable carries on (all in a straight line through the wheelbox) to the next wheelbox. BTW, if you wanted 3, 4 or more wiper arms, you can just keep adding on until you run out of inner cable to feed into wheelboxes.
The shafts that stick out through the scuttle (to attach the wiper arms onto) can be set to any angle you want; there is a spacer between the wiper arm & the scuttle, angle cut on one end. You make your own (I'm using thick-walled black plastic tubing) with whatever angle suits your build.
The only real issue with this system is that there are bronze bushings in the wheelboxes that you need to grease every couple of years. If you can find a Spitfire, MG, etc., take a look under the hood, and you'll see how simple and ingenious a system it is...and tailor-make for Locosts.
Here's a system on Ebay... http://cgi.ebay.ca/MGB-windshield-wiper ... %26ps%3D63
It's a little grubby, but you can see the motor, cable, wheelboxes, etc. Bear in mind that the wheelboxes can be placed anywhere along the cable, as close (or as far apart) as you want, oriented in any way you like, the cable can go around corners easily, etc.
I bought a whole system (used, but virtually new) locally at a British car specialty place for around $40CDN. For the wiper arms & blades, I bought new, stainless steel Austin Mini parts. Spridget would also work. I looked at other systems, but nothing else was remotely as easy to work with...