I was looking for inspiration in one of my favorite places -- the CLEARANCE racks of a used bookstore -- yesterday, and came across some worthy advice in a book that cost me a buck: "The E-Myth Revisited", by Michael Gerber.

He says (paraphrased from memory), make REALLY sure your business is going to solve a significant real problem for a lot of people, otherwise it isn't worth the pain/heartburn/stress/etc of making it fly.

It doesn't sound like your app -- as described -- rises to that level of urgency. Having put myself into a flaming tailspin with businesses that didn't meet this criteria several times, I hope my repeating it for you all will pound it into my own brain so that the next time I walk away from a paycheck (yes, I feel it coming!) it flies high enough to get me over the pain mountains.

I agree with the other responders, make it FOSS -- your employer might give you more time to work on it in this case as a joint effort -- and profit from the increased notoriety and potential support consulting. :D