Yet another Summer of Code idea (if it's not too late)

Hierarchical ticket views.

Let’s say I have a Project, with a number of Tasks under it. It would
be nice to be able to group the Tasks under the Project, potentially
with the ability to hide/reveal the child tasks. Trying to do this in
raw SQL would be truly hideous, though I’m sure there is some bright
girl (all the best SQL coders I know are female) out there who could
figure out a way to do it.