Is possible to search for questions and sort them by the votes of the most voted answer (not the question)?
If I understand your question correctly, one way to do it would be to add
is:answer to the front of your search, then click on the "votes" tab to order by votes.
For example, to search for the highest voted answers concerning "garbage", you could do this:
Then click the "votes" tab on the search results page.
(FYI: according to the above search, Eric Lippert has the highest voted garbage answer on SO =P)