Here are a few alternatives that I've discovered – after I've written my own version, of course...

http://www.kinvey.com/app-cost-estimator

http://howmuchtomakeanapp.com

http://freeappestimate.com

I'm not sure those rates are realistic, they seem to be at the higher end.

Well, the costs vary depending on a lot of factors. The prices are based on my experiences here in Switzerland.

I've been thinking about adding selections for country and rate, but in the end, I didn't have enough data and decided to keep it simple in the first version. However, I'd be very interested to hear from other developers around the world what they think about it.