Yep, in fact I think a lot of vfs are like this - doesn't /proc/ query the kernel when returning parts of its tree (e.g. representing processes).

wrt the fs representing queries: one of the tag systems is like this, it represents tags as folders, and the search for term 'X' and 'Y' can be found under either folder ./X/Y/ , or ./Y/X/ ; obviously, every new tag combinatorically expands the virtual space.