I've been working on something[1] very similar for some of my own apps. It is available under the MIT license. What license are these recipes released under?
I decided not to mask the icons and opted for pre-masked PNGs because I couldn't match the style as well as I could in Photoshop. Yours is looking very good though. Maybe we should merge?
Not being able to modify even the highlight tint colour of the UITabBar is a mini peeve of mine. To me it doesn't make much sense to force blue when a lot of the other UI elements have a tintColor property which works great.
I didn't have the time to do a custom one for my last project so we stayed with the standard blue in the end.
Edit: nice work though! Nice to see a thorough explanation of your thinking.
I wrote something similar for an app that used Titanium. All javascript, of course, with select-state images and a 1x42 pixel background. I'll see if the company I wrote it for will let me release it as a snippet.
I decided not to mask the icons and opted for pre-masked PNGs because I couldn't match the style as well as I could in Photoshop. Yours is looking very good though. Maybe we should merge?
[1] https://github.com/briancollins/BCTabBarController