It's just plain stupid to ask for "bonus" when you found a block when you are mining at a pool that dedicates on paying everyone exactly the same per each share they do...
Are you willing to accept LESS when you don't find a block, so that the pool can fund the bonus paid to the one that found the block? Hummm? Don't think so...
Just go mine on your own and see if you will ever find a block.
Personally tho, I might be leaving the bitcoin mining scene soon, due to the rather crazy increase in difficulity, perhaps Scrypt rigs might be a better idea, tho it takes a long time for them to pay off..