I think people worry way too much about gunner/non-gunner. If you want to raise your hand and ask a question, so long as it is not inane, I think you should do so. I think the "gunner" stigma creates a bimodal distribution of participation, thus exacerbating the 'gunner' problem. In other words, if people weren't so worried about being perceived as gunners, the class would be livelier, and the true gunners wouldn't be so annoying.
Take it from me, I was a gunner.
PS: I much prefer an honest gunner--one who shows up to class on time and prepared, asks good questions, but is not arrogant/filibustering--to a lazy slacker who thinks they are entitled to speak despite quite obviously not preparing. If you're going to make comments like, "Who's Lord Coke? His name is _awesome_," then perhaps silence should be your path to eloquence.
PPS: Regarding hypos--if you can construct good hypos that get at unresolved problems in the caselaw, by all means proffer them if the professor is receptive. One of my hypos more or less made it onto the final exam, and I breezed through that issue. Also, it's fun, and might even turn into a note topic! Just don't feel the "need" to present hypos--in general, don't speak unless you have something interesting to say, and honestly want to learn. If your motive is to impress others, reconsider raising that hand