If not, are there alternate solutions that can let me accomplish this? Do I need to develop my own plugin?
ShrimpTest is a simple and easy way to add AB testing all over a site:
The Premise plugin from Copyblogger integrates with Google Optimizer and lets you create multiple versions of landing pages. It also contains some templates and lots of copy writing advice.
I recommend a AB Press Optimizer it lets you run experiments in your post, pages and custom post types. It also has a PHP function so you can implement test directly into your theme.
I started working on a plugin for A/B testing in WordPress after finding myself unsatisfied with existing options. Doesn't support posts right now (only Pages) but support for all post types will be easy to add. Haven't submitted to plugin repo yet but it's on github.
I got annoyed with the plugins available and wrote a simple Wordpress solution. It actually learns from successes and uses a very basic algorithm to serve the best performing option more often.
You have to use it in the code as most of my website is in custom PHP but it may be of help to someone.