[G.R.]

If I was buying a car I would insist upon using an escrow service. The funds transfer quickly. That is how I insisted it be done when I bought my FIA. When I took delivery and signed the paperwork and notified the escrow company the buyer had his funds the next business day(due to the time difference between the west coast and Chicago only).
I put a deposit on the car in an escrow account, then arranged shipping, once the buyer verified the escrow had the deposit, he ok'd the release, the day the car was shipped I put the balance of the funds into the account, to be released after I accepted/approved delivery of the car. I paid the escrow service fees which is usual buy the buyer.

An escrow service protects both buyer and seller....buyer recieves the goods as decribed by the seller and the seller recieves his funds in full. Escrow is used in real estate all the time for that very reason.

Unless it is a scam I can't understand why the seller would balk at using an escrow account he would have his funds in his account in a max(usually) of 1 business day. The escrow company will take care of all the paperwork involved in tranferring funds, the buyer has no knowledge of the sellers account information nor has the seller knowledge of the buyers account information.
FWIW Good luck