I don't know your market, but I can give you a little personal experience that my help. I purchased a house that was for sale by owner. The owners were not willing to pay any brokerage fees, seller or buyer. The house was listed on Craig's List, and the owner received many calls from interested buyers agents asking if they were willing to work with them (pay a commission). The owner was not willing to do so.
I knew that particular area very well, and was not working with a buyers broker. I was the only person that looked at the house, and was able to get it for a good price.
While the outcome was great for me, I think the seller would have done better had they been willing to pay a commission to buyers agents. Because the sellers were not willing to do so, many interested buyers were never made aware of this house.
With every MLS listing published to dozens of websites these days, lots of buyers are looking at houses on their own all the time. They could care less what incentives you have for the agents. That's why I would also second Samuel's suggestion of offering incentives for the buyers ..rather than their agents. Closing costs can always help, ...the plasma tv's are intriguing though I have yet to meet a person where gifts like that was the pivotal factor in deciding to purchase. They just make it more appealing. ...which in this market is probably what you need as much of as you can get.
To me....I love a 4% commission obviously but ultimately I am going to show houses that my buyer wants no matter the commission. I will say that it is difficult to show a home below 3% but ultimately if I think my buyer's want it I will do that.
Another idea may be to lower that commission to 3.5% (u'll see the same result) and then actually offering the buyers something like a flat screen TV or covering closing costs....etc. This will get the buyer excited as well as the agent!
Just an idea...of course realtors would all love to sell homes with higher commissions but if I'm representing the buyer my first job is simply to make sure that it is the home they want.
Leave it up to the listing agent to get the word out about the commission and buyer's incentives.
You have hired a professional....You have a great idea to spark interest. Now.....sit back and enjoy the ride. If you have done your homework, you have inspected what you expect from your agent and, you have listened to their direction and followed their recommendations, there should be nothing left to do but pack. Good luck on your sale.