For a list of some of the places in Southern 
Cali, check out http://www-
scf.usc.edu/~ckawakam/shop/

As for Vegas, there is the following...

Alternative Reality Comics- 4800 S. Maryland 
Parkway across from UNLV

Comic Oasis- 4250 S. Rainbow @ Flamingo 

CheeseBoy Comics- 8826 S Eastern Ave # 113

Kool Kollectibles- 5140 W. Charleston Blvd. and 
953 E. Sahara Ave. #9B

Dreamwell Comics- 5706 W. Charleston Blvd

Triple J Hobbies- 4130 S. Sandhill Rd

Those places have a good selection of manga and 
anime, but no cels. Have fun!