Ideas looking forward
It's possible to make vanity address mining much like regular bitcoin mining, in the sense of tracking the total work completed by each participant, and possibly distributing rewards to all participants rather than just the finder. The idea would be, if somebody wants 1DanieLRH, post the bounty for 1Danie, and keep track of how many addresses each miner returns. Eventually, a matching address will come back, and all of the partial matches will make it possible to determine the division of compute resources.
It also wouldn't hurt if the pool posted the portion of the bounty that will go to whoever solves it, rather than the amount paid by the customer. It's a letdown to see a bounty for 0.1 BTC, and only receive 0.08 on completion.