Came across this and thought it might interest some of
the metal manglers that lurk about.

http://xlhybrids.com/products/conversion

Seems like this would be a fairly simple project for
most moderatley equiped shops. The only difficultly
would be sourcing the electric motor and inverter to run
it. An old laptop with some MCU development software
to control the motor would be intresting to experiment
with.

Best Regards
Tom.