[TwoBit]

The first gen of PS3 included a PS2 on board.

[dfox]

I believe that even the slim PS3 versions without full-blown GS+EE hardware still include the PS1 CPU somewhere in a role of IO controller.

[gumby]

Fun to know, thanks. I was out of the "biz" by then.

[willcipriano]

Game boy advance had a game boy on board as well.

[SSLy]

And Nintendo DS has a GBA core/CPU on board.