Dave (LionsPaw)'s MAXine...
viewtopic.php?f=35&t=14652 ...has a cool horn button. He got a cheap key-fob radio relay thingie and mounted the transmitter in the horn button, and the receiver in the horn circuit. Thus he can take off his removable steering wheel without unplugging wires.
It's clean, practical, and locost, and it's pretty amusing as well. Not only can he take the steering wheel into the restaurant with you when you break for lunch (which is an effective theft deterrent in itself), he can honk at people who mess with car, and never has to leave the table.
But I'm getting OT here. My point is, you could put two of these transmitters in your steering wheel to activate your turn signals.