MIMF

Is there any use of blue tooth technology in luthiery (or something similar)?

The concept of placing a blue tooth transmitter in the instrument, which is sending signal to the amp wirelessly?

As I looked at Dan Gilmore's electric violin, the output jack just seemed too big, and out of place on a smaller instrument.

Steve, yes, it's been done before. The Gibson Firebird X Robot guitar features Bluetooth, and some sort of crazy expression pedal etc. that accompanies it.

Is it a good system? Worth using or expanding?

I've never used one of the Firebird X's, I've only seen it on the web. Given the performance of other Bluetooth audio equipment I've used, it certainly could be done quite well. The low power consumption would be an attractive advantage. Designing a custom system though would be a fair bit of work, so finding something that could be adapted to the purpose would be the trick.

Actually, a while ago I modified some studio quality headphones with the guts from a broken set of Bluetooth headphones. They work great! As far as I know, I'm the only person with pro audio quality Bluetooth headphones! <g>

I've been planning to implement bluetooth as an onboard headphones transmitter, glad to know it can work.