A/B testing is an ongoing process
We've been testing a number of pages on our site. Each time we test a page, we learn that we need to test another page because the traffic from a targeted page is moving to a non-targeted page. What we've really learned is that even for a moderately complex website like ours, the best tests are funnel tests.
I also agree that funnel tests are very powerful. Most companies start creating relevancy by using symmetric messaging - meaning the website landing page reiterates the messaging from the acquisition channel that brought them there. The natural next step here is to keep that relevancy throughout the funnel. If it was a sale on cat food that brought them to you, then bring them to the cat food sale landing page but continue to offer relevant cat products and offers all the way to checkout. This type of customer experience really shows the power of relevancy and will take your conversion to the next level.