There are companies which you can pay to produce mysql fixes you specify. One of which is Percona. Won't be as cheap as gittip or something similar, but you'll get the results without relying on a bug hitting the top of someone elses' priority list.
So Percona is able to create a customized fork of MySQL for you? won't that create a maintenance problem in the future?
I mean, you won't be able to get official update releases anymore.
Percona already runs their own MySQL fork. (http://www.percona.com/software/percona-server) They include various patches that their customers have asked for and also update it every time Oracle releases a new MySQL version.
