Do you think there would be immediate interest? I have considered building a mobile development tool, but didn't think mobile dev. was popular. However, it
might be of interest to amateur programmers who lack access to laptops/desktops. Would be easy to build :)
Hard to say: it hasn't had much of an opportunity to become popular, because it hasn't been a real option so far ;)
That said, my sense is similar to what yours sounds like -- the audience will remain small, just because it'll never be as fast, even after a tool like yours cuts down the entry time.
I'll ask around and try to generate some use cases or niches where mobile could take off, and get ahold of you if I do. I remember Paul G. talking about it a year or two ago, maybe if you can get ahold of him he could share his thoughts. Meanwhile -- nice work.