Edit: i didn't realize there was 11 pages and the OP found a similar project lol. Anyway, still might be useful info for others. Delete if not wanted here. Sorry!
When i worked at WV dmv records dept we had a "message forwarding form" that would allow someone to send a message to the last known registered owner without divulging personally identifiable information but there was a lot of reasons it may fail. If the person moved, if the 911 administration changed the address from the old route/ box numbers, if the person died, or if they just didn't want to reply they weren't required to. The person looking for the vehicle would fill out the form with as much info about the vehicle as possible, and we'd send it to the address of the last known owner. During the info gathering we would do, we would run a check on the national database and if it was registered in another state newer than our records we would let the seeker know which state since that's not pii and they could check with them to see if they had a similar process.
You may also ask the dmv rep if they can tell you what county so you can check junkyards in that area. Some states may consider that pii though.
Alternatively a private detective would be able to get more info. Good luck and i hope you find it!
