OK, so my little sister's 11, and here are some shows she has enjoyed that might be fun(some are already listed)...
DRS
The Light in the Piazza(she didn't like it at first, but has now gotten more interested in it)
Spelling Bee
Spamalot(a bit questionable)
The Producers(both her and my cousin saw it at age 9, they enjoyed it, but quite a few things went way over their heads)
Hairspray
The Lion King(I went a with a few friends, and their parents, to see it, everyone in the group from ages 11-50something enjoyed it)
there are probably more, but these are the ones I can currently think of.
oy with the poodles already!