Shucks, I had pretty much exactly the same idea a year or two ago, but it stalled when I couldn't find anyone to pay me to develop it.

May I ask for details about the platform/architecture?

Also, the usage caps seem low to me, across the board. If I ran a site that I expect to get major mobile traffic, it might make me nervous to see that the top tier is only 10k hits/day (even if in reality I'd never come close to that)