Hi - I found this topic googling for ways to search users. Unless I find a better option (none so far) - I will add that functionality to the amr-users plugin. It currently does customisable listings of users, pulling whatever info is in the usermeta (eg: as added by register plus and other plugins). Note current version is soon to be out of date - major update on the way aimed at higher volume sites.
I was thinking of admins searching for users, but I see above people are thinking of viewers (maybe logged in users ?) searching for other users.
customised search results:
I was thinking it could work well with my userlist (amr-users) plugin as developers could use the list customisation mechanism to define how the search results should look, and possibly also which fields to search.
If anyone would like to clarify their ideas of what they would like the search to be input (what criteria etc) and how the results should work, let me know.
I could bear that in mind as I flesh out how I think it should/could work. Currently the userlists are available as a shortcode [userlist list=2] for example. I can see this also being used to deliver search results.
Just had the idea that a customised list as well as posssibly controlling what fields to search, could also be used to limit the search (eg: exclude all admin and moderators for example)