I am having a hard time finding the PS3 Collector's Edition in my city.

K-Mart was supposed to have them, but then changed their inventory.
GameStop is all sold out.
Best Buy has several XBox 360 CEs, but no PS3 CE.

Is there any other chain that carries the title apart from those three ?

Depends on where you are in the world. Try general electronic shops, they sometimes carry games, they might have it.

Chains that deal specifically in games/electronics like GS and Best Buy are the least likely to have them. They drive their inventory based off of preorders, so unless someone cancels, the chance they'll have an extra CE lying around is slim. People don't think to preorder at mom and pop type stores, or stores like wal mart (as much as I hate wal mart), so those are a better bet.

I am in San Diego and as far as I know there are no small privately-owned game stores left here. Walmart used to have CE on their website but it has since been removed so I don't think they carry it.