I've just bought a Shadow SV1 pickup for my fiddle; cost peanuts, fitted in seconds, no need for pre-amps, sounds amazing amplified & in the studio:

http://soundcloud.com/sedayne/pendle-sonata-1st-june-2012

Tried it on stage last night for the first time at the Lunar Festival. Simply awesome. It even picks up the tone of whatever sort of mute you're using.

Drawback? Well, finding someplace to stick the jack socket is always going to be an issue, but after some deliberation I fixed mine to the tailpiece & tied it up with nice folksy jute...