Admittedly, this info kind of dated, but I'll bet that the underlying problem is always similar...
Back in the distant '80's we imported a Canadian-built sailboat into the US. From BC to Oregon.
Oregon is a "full title" state, so our Marine Board needed the prior title, signed off, to create a new OR title.
I had none to give them since boats of that size did not require a BC title at that time.
I did have the bill of sale and the current pre-purchase survey that certified that the seller was the original purchaser. It took both of those documents to satisfy the OMB that the deal was all legit and then they created a new title for us.
It took a couple of letters and a phone call or two, but I knew that their official concern was inadvertantly creating a title for a stolen boat.
All I needed to do was convince them that my purchase was all Kosher, as it were...
So, while it took over a month instead of a week or two, it all worked out fine in the end.
We sailed that boat a LOT for a decade before selling it and hunting down the larger boat that we still are sailing now.
It seems like you should be able to do something like that to get your boat titled in the US.