have you looked at
EV Photo Album: Our Electric Cars on the Web to see what others have done?
The CRX would be my last choice unless I could afford lithium batteries, that car is not built for much weight, when I was doing construction work I learned right away that I could not set my tools to far back or it would lift up the front end and make it unstable above 50mph.
I would go for a vehicle like a Kia, they are common and the engines have timing belt issues so they die early and often.
http://cgi.ebay.com/ebaymotors/ELECT...#ht_500wt_1021
This one on Ebay someone already started and is selling as a part done project.