I feel for you. Last year I looked up several award winners in my committee and a few of them had one 1st author and maybe a co-authorship or two and a couple individuals even had no 1st authorships. My 'stats' are similar to yours but with additional co-authorships and longer work experience. My impression (though this is pure speculation) is that the reviewers often have a specific type of applicant in mind and when you deviate from the formula, you need to work pretty hard at emphasizing why you're still deserving. I know a lot of applicants talk #pubs, previous big scholarships etc. but based on my experience and sleuthing, it seems something else is also at play (e.g. luck, wording or writing style).
Speaking of having a sexy research subject, in my proposal I made minor changes to further emphasize the project's appeal and dropped a couple of the more technical sentences. One theme I noticed in previous award winner's applications, was that there was a lot more talk of relevance than detailed methods (as opposed to what you might have written for you department's candidacy/project proposal). Not sure if this change helped but after my first rejection, I decided to give it a shot.
Good luck on your application next year!