We've gotten some enthusiastic responses about the idea of a developer/beta tester matchup program between Ask Different and Stack Overflow. My thanks to everyone who has volunteered so far.
The next step in making this happen is getting some apps for people to test. Since there isn't a meta for just OS X/iOS developers on Stack Overflow, we think one of the most effective ways to attract developers' attention to the program is to stick an ad on the relevant tag pages over there.
I am not a designer. I have zero Photoshop Fu. I can ask Stack Exchange's designer-in-residence to put something together for us. But, the community promotion ads for this site came out so well that I thought I'd open the design up to the community's imagination.
I'm not even going to stoop to posting what I hacked together as an example. Just post your 220x250px image as an answer and the votes will decide!
(Posts are not subject to the parameters of the community promotion ads, since these images will be downloaded and run on Stack Overflow "by hand", not by the run-community-ads bot.)
I lied. I'm going to inflict my mockup on you.
Clearly, these decisions should not be in my hands. You should probably help.