Are Intel HD 5000s on-board video common yet? That would handle it pretty well.
I would personally gun for an i-5 series 4, which I believe would have an Intel 5000. I recommend on-board because they don't produce much heat and frankly dedicated seems overkill just for one game from 2009.
I haven't seen any HD5000-5200 laptops yet (not that I've been looking). I still haven't found a cheap HD4400-4600 laptop. --- Every time I try to go where I really wanna be it's already where I am, 'cuz I'm already there XBL, PSN, Steam, Origin, BSN, GFAQs, MC: PhilOnDez
FYI: To the people who don't actually play Sims 3. Sims 3 can be heavy on your computer specs. Ya, not hard to run just the base game, but when you load on tons of expansions and have all that stuff running at the sametime, it can get crazy.
And don't even mention large custom worlds. --- http://happyscrub.com/tierlist.jpg