AFAIK, the request to have upvotes/rep gain for editing was rejected, though at the moment I can't find the references.
However, if/when someone edits my question or answer in a materially helpful way (at least in my opinion) I usually feel that I'd like to thank the editor in more than words.
As such, do you feel that it would it be appropriate to up-vote an editor's Q or A totally un-related to the one of yours the edited? (assume that the post to be upvoted is not so bad as to have the upvote be grossly distorting the balance of the content, yet not so good that you would have upvoted it in the routine scenario.
If you feel that's inappropriate, what about when you explicitly go hunting through their posts to find one you'd feel justified to be up-voted on the merits of its content?