1) Make backup offers on all the current listings so you have an offer in place rather than waiting for one to fall through. Not all sellers will take a backup offer so this might or might not be productive. 2) And either you or your real estate agent could do a direct mail piece to all the owners to see if anyone is interested in selling.
For a real estate agent to solicit business by talking tax advantages would face some sort of disciplinary action unless that person was also an accountant.
Also, the house recently passed legislation with a provision to extend the exemption on mortgage relief; whether it passes the Senate is anyone's guess but there are too many unknowns, in my opinion, to ethically use the tax advantage angle to induce someone to sell.
I would go with number 2 above if you are motivated. Good luck.