Just do an installment sale, for the higher price now, close ASAP, and you carry back a note (a second, if necessary, if they're getting a mortgage) for $20K or $50k whatever, due in January 2015, as long as they can pay it, and aren't depending on a whole . Hell, you can have the money stuck in escrow even. They still close today, pay everything today, you just don't realize some of the gains til later. You must not be able to access that money for any reason until 2015, even if you wanted to.
I think this should work.
Disclaimer: check with your CPA, obviously.