Well it's the entire pull request we where thinking of (i.e. push based notification for transactions and blocks, plus generic getblock).  So anyone who contributes to the finalizing of this pull request, once it's actually integrated with the client.

After some additional consideration we are not offering this bounty for a solution that is not integrated with bitcoind.  The goal is to get the feature we want and promote it for inclusion in the client so the community gets the benefit as well without the need for other tools.

However we would definitely pay at least a partial bounty to an interim solution that is client integrated, but not necessarily this complete set. Such as pull based equivalents, or the ability to check arbitrary addresses for payments.