This is not really an answer to your question, but after reading your post I can't help but think that maybe you should try out test-driven development, and see whether that improves your job satisfaction as a developer. I don't know exactly why you feel you're not efficient (enough) as a developer, but for me TDD cancels out many of my personal failings which would otherwise hamper my development work (like procrastination in the face of a big task, indecisiveness on what to do next, over-engineering a project rather than starting it, and more). This is not what TDD is about primarily of course, it's foremost a design methodology, but these are nice side effects which make my work more enjoyable and productive. Maybe it'll do the same for you? And if not, at least it's a step in the right direction towards full-time testing.

As an aside, one of the links adrianh gives in his post lead me to a blog-entry which has got to be one of the best articles on TDD-related topics I've read recently.