According to a answer to the SuperUser.com question "How can I force Windows 7 to REindex a folder?", one solution is to toggle its "i" attribute twice.
Recently (12.4 I guess), Opus got support for setting that attribute, so that can be done easily with a button that does:
SetAttr TOGGLEATTR i RECURSE
SetAttr TOGGLEATTR i RECURSE
I only made a single test and it seems to work, even when the content does not matter because the attributes are what need to be indexed.
If you try that, please let me know of the result.