The problem with multiple namespaces has been noted in
bug 11313. I've fixed
it on the devel branch.
That's something that I believe Robert
(who's been maintaining our
Lucene-based search module) is working to improve.
I'm working actively on this and other issues like spell checking and ajax
suggestions. Most of it is implemented, just needs more testing.. I hope to
finish it and hopefully bring it online by the end of the january...
Awesome. :)
-- brion