Let's say I see a question with bounty of 100. I like that question. I want it answered. I'm willing to boost bounty with 50 of my own rep. Is there a way to do this? I guess not, so are there any chances for it to get implemented?
This has been discussed on MSO a few times. The best read is probably, More than one person should be able to offer a bounty for the same question at the same time. Right now there is no way to do this (though I like the idea).
At the moment, the best option is to offer a bounty on the question after the first one expires.