Good ideas. Something like this?
http://www.rentron.com/Volt-Meter.htm
It would satisfy the nerd in me to drive both the cheapest AND most instrumented NEV in existence.
Or a DMM with an RS232 output:
http://cgi.ebay.com/Mastech-PC-RS232...QQcmdZViewItem
Too expensive for Project Forkenswift, but I didn't even know they existed until you suggested it.