Thanks for the development, tests and updates.
Compared to the traditional crosswiki search, this interface has some potential weaknesses. 1) Custom logos/icons are used, which have not been thoroughly tested in the past and are vastly inferior to the actual project logos (for instance they're black and white and the icon for the dictionary focuses on the Latin alphabet). A test is needed against the normal icons to see if there is a proven improvement: otherwies, just use the actual logos. 2) Showing a snippet means you're only able to show one search result from each wiki, if I see correctly. Cross-wiki search is most useful when one searches an ambiguous term which might yield unexpected results, so it takes quite a bit of optimism to assume that the first result will be effective. I suggest to test an alternative version where either some wiki gets more results shown than another (e.g. if the match score is close) or every wiki gets more results shown and there is no snippet. 3) The images take a lot of space. In many of my informal usability tests (looking over the people's shoulders while they complete wiki tasks at workshops), I often see people not finding the search results at all because the results are below the fold or just because stuff on top acts as a visual barrier. I suggest to try a variant without any multimedia results at all (there's already the multimedia tab anyway), or where they take much less space, so that the actual search results are as close as possible to a region where they're visible to the user.
Nemo