I went through this hassle in Oregon. Prior Washington title used number of long gone engine. After a lot of talking and a trip to the State Police to confirm no frame numbers, then Oregon just assigned a VIN #, which was of course the serial number. But they didn't like the fact that the serial number was on a removable plate, so they stamped a cheesy metalic sticker and stuck it on the door post. There was an up side to this, I did get the state police to wire brush a good portion of the frame.
