You are most welcome. I like the way you think about the the buyer calling it in but if the 2nd sale was financed I bet a condition of the financing would be that the lien would have to be cleared up.

Here is the IRS link regarding how they would go about doing that:
http://www.irs.gov/pub/irs-pdf/p783.pdf

The seller would already have the money. It is the new lender or their title insurance which would have to come and clean up the mess.