Search inside of a tree of nested pages

Currently you can search the entire server. It would be better if it was possible to limit the search to a specific space, or even a tree of pages. The ability to limit how many "levels" of children to go down (i.e. parent > level1 > level2 > ...) would be useful for large networks of tree's.

eg: ASPACE:FAQs and down 5 levels of children