I don't want to hold my breath (THAT TRAILER WAS SOOO SEXY OMG I'M SUPER EXCEITEDAGSEFAHS) but I did see areas that looked exactly like Los Santos and San Fierro
0:07 - 0:11 SANTA MARINA BEACH (Remeber when you do the OG Loc missions to steal the tunes for his crappy party?!)
0:17 - 0:19 THE GOLF COURSE IN SAN FIERRO (You meet that asian girlfriend by the bushes!)
0:19 UNDERNEATH GANT BRIDGE (remember when you do the mission for Wu Zi where you're on the Cargo ship?!)
0:20 - 0:22 l LOOKS LIKE MOUNT CHILLIAD (where you run that crazy mission for those cops where you chase down that guy in that cabin, kill him and take pics)
Several shots look like downtown Los Santos (Look at the wall at 0:53!)
1:10 VINEWOOD? THAT CAN'T BE ANY MORE OBVIOUS! I played San Andreas religously (KIFFLOM!)
Why would you be able to see downtown LA from San Fiero... That's a ridiculous assumption.
I'm pretty sure this game is just going to take place in Los Santos, but with a map twice the size of Los Santos in GTA San Andreas.