Seems mobile is a good space to be in...
Without anything first hand experience I get the feeling that advertisers are paying to much at the moment for ad space in iphone apps, given that it's a relatively new advertising direction I don't think it's really stabilized yet and going forward it will probably become harder to pull the same kinds of number from that same traffic.
Anyone with insights into Backflip Studios? Number of people working full time, how much money spent building this range of games?
The amount of money we spend making a game for iOS or Android varies a lot depending on the scope of the project. A game like Paper Toss or Strike Knight is primarily art bound, so if you have a great in-house artist or two (we do) then you can figure out the cost based on 1-2 months of dev time for one engineer, 1 month for art, a few weeks for sound, and a few weeks for random QA/marketing/etc at whatever pay rate is applicable to your area. If you need to replace any of those components with contractors, your cost will definitely increase.
You're on the wrong side of the Atlantic for me though :)