Conversion Rate Expert Needed

Hello. I am wanting a conversion rate expert, who can work with Magento. They will go through my site, do split testing etc, and make any changes needed to site, checkout etc etc. Please provide examples of work done in the past. Please note, money will only be paid once the conversion rate has got to a standard needed. The site will need to be analysed with usability studies etc etc. You must be able to do the work, and to a very high standard. If the price is right, and the work is to a very high level, i have a number of clients to use this with. Thanks