We faced the same problem, and built an A/B Testing Framework at a Hackathon this month that allows you to just drop in a line of code and run all the experiments through a web interface without app updates.

The framework is not quite ready to ship yet, but we built a fully working proof of concept, and are looking to complete it and put it out there.

You can read more and watch a video demo at the website: http://fliptest.io