The only one I know about is through
AwesomeMod. Also you should look at
RTFM, that gives the description of the features in the mod.
If search the AwesomeMod section for "more than 8 in a household", you should get posts about how to work it with The Sims 3. I don't use that feature, but I know you will have to play it different than in Sims 2.
I think
Sims3Tinkers may have one too, but I don't know much about them.