I have seen hints that this is possible, but many of my resources tell me this is not possible. They also tell me you are the master of all things WAC and have tried this if anyone has. I also have seen a presentation http://www.slideshare.net/BobGerman/search-first-migration-using-sharepoint-2013-search-for-sharepoint-2010 hinting it's possible by modifying the search results templates.
1 Answer
It looks like it is. Have you seen this article referenced by Bob and Max? http://blogs.msdn.com/b/murads/archive/2012/10/11/utilizing-web-apps-2010-to-get-powerpoint-previews-of-sharepoint-2010-content-from-sharepoint-2013-search.aspx
There is a lot of Display Template work involved, but it appears that you create a display template that uses the 2010 preview features.