Some links

Federal Motor Vehicle Safety Standards and Regulations Oregon does not seem to require anything in particular -- but they will require a VIN inspection if they think the vehicle does not meet these standards.
PART C - INFORMATION, STANDARDS, AND REQUIREMENTS Not sure if this will be helpful or not.

ASSEMBLED, RECONSTRUCTED OR REPLICA VEHICLE CERTIFICATION Not sure if that form will be appropriate or not...

Street Legal?

What does it take to qualify as street legal? I assume you'd have to get the license plate, have air bags (or something), etc... but what are the actual requirements? How do we find out? Do we wade through all the DMV logs? Is there an easier way?

Oregon DMV 2005 Vehicle Code Book

While it is hard to narrow down specific requirements because of things like the law stating that a standard must be made (but not what such standard is) there are specific comments about EV.

Page 23 of Chapter 815 (Vehicle Equipment Generally) says in 815.300#9 that EV are exempt from the pollution control system requirements.

I did find some more information in Chapter L. Vehicle Types:

Passenger vehicles are titled using the VIN from the frame (or an MCO if it is a New Passenger Vehicle).

Electric vehicles are registered as per ORS 803.420
(looking that up, it is $27/yr)

Electric vehicles are subject to residency/domicile, financial responsibility, and odometer requirements. If a vehicle is manufactured without an odometer, the Exemption from Odometer Reading Requirements, Form 735-6745, must be completed. Electric vehicles are exempt from DEQ requirements (ORS 815.300)