I'm a relatively new user on all 3 sites. But already I've accumulated a ton of reputation points on Stack Overflow which I could use as bounties on Server Fault. My areas of expertise are just very lopsided towards programming, so I can help on one site but I need serious help on the other.
Ask good questions and you'll almost always get answers. Bounties, IMAO, are a crutch for people who don't want to spend the time to ask a good, answerable question. I'd be happy if they went away entirely.
Change your name to Linus Stallman and claim to have amnesia. Ask for help from the community in restoring your memory and identity.
It could very well be that nobody viewing your questions knows how to answer them, I have found this to be the case numerous times on SF. Really difficult questions like LVM metadata being out of sync when using DRBD often gather dust. If you can't find it with Google, (in my experience) you can't get it at SF.
A bounty would likely end up in an answer you can't use being selected automatically after the bounty expires, if the question is already gathering dust.