Judging by others around here, it seems you stand a better chance calling and checking with individual stores than ordering online right now. Some buyers have noted that their local store has stock while others don't.
Well, the last unit was at the store when I bought my S2 today and it got sold in front of me... but then again, the store is about an ocean away from you... literally!
I just called my local one. They actually have at least a few 256gb in stock. He not able to tell me exact numbers nut they have a decent amount. Now time to decide if I will pay them a visit tomorrow.
He said they were all sold out of accessories though.