Didn't
Codename: Kids Next Door also reportedly tip the hat to Foster's once? I have not seen the episode in question, but there was a thread about it here:
http://www.fosters-home.com/forum/sh...?t=1322&page=2
Being spoofed by a fellow CN show is one thing, but I would be very surprised if Foster's ever shows up in the likes of
The Simpsons,
Family Guy, etc. It was a popular enough show in its own field, but it didn't achieve nearly the same all-encompassing cultural impact as the likes of
The Powerpuff Girls and
Spongebob Squarepants. Whereas even folks who don't watch much contemporary kids' TV could probably recognise who those characters are, a Foster's-based gag would be a heck of a lot more esoteric.