About a dozen times in the last two years, I have been the first to answer a question and I end up spending more than a few minutes—maybe 5 to 15 minutes—editing away at an answer (without saving). Then the dreaded notice at the top of the screen says "This question has been deleted". I don't have a lot of choices at that point. One is to hope the question will soon be undeleted and then (maybe) I can press "Post your answer". More realistically, I have to close the page and lose my answer.
The number of edits proposal is a non-starter in my view since it doesn't help share my work unless I game the system by saving after each word's entry or something cockamamie like that.
The substantialness of edit strikes me as more useful and reasonable measure especially if it applies to not-yet-saved answers. A threshold of maybe 250 characters seems about right, unless it took me an hour to generate a great answer in just 175 characters. :-)
Eric's idea of surrendering a questionsurrendering a question seems the most useful mechanism, especially if there is any evidence of substantial effort being made to answer it. Minutes of typing, number of characters, number of edits, etc. Is that technically feasible?