Something like this, (quick mockup), albeit with a lot more work put into it. (Especially the look of the bee/ trees).
In case you haven't seen it, a couple of weeks ago I made a list of banner ad suggestions to another dev on here, in this thread. I think a lot of my points similarly apply to your banner too, so I highly recommend you check it out, and hopefully it can help. Like others here, I agree your newer banner is a big improvement, but I also feel the same as NickFalk that a complete redesign of the banner will be more effective.
