There are A/B open source projects out there why not just go with one of those instead? Why reinvent the wheel? Also ppl have been splittesting using for example Google Websiteoptimizer for like since it was made public. I know I have. Even written a plugin that integrates directly to the TinyMCE editor. Couldnt get creation of tests from inside of WordPress to work last time I tried ages ago. Could probably make it work now.