Hey Fred,
I was considering the same when I was doing my build (kinda wish I did). Anyway Sterling Sports Cars made one:
http://www.sterlingsportscars.com/Electric_Sterling.htmlAlso there was a company in India that wanted to produce them:
http://www.autoblog.com/2014/12/09/supernova-ev-first-indian-electric-car/Anyway it's something that's been done quite a few times (somewhere there was a video of a pretty quick sterling or Nova EV running the quarter).
You could alternatively look for EV kits made for beetles as a starting point (though many of them contain just low-hp motors).
Radek.