It seems that two of the Grand Theft Auto games might be coming to PSN as PS2 Classics if these ESRB ratings are anything to go by.
Grand Theft Auto III and Grand Theft Auto: Vice City have both been re-rated by the ESRB for the PlayStation 3 with SCEA as the publisher. Due to that fact we can best assume that they will be coming to PSN as PS2 Classics. Both were huge titles for the PS2 back when released so it makes sense that Sony would want them available digitally.
We will reach out to both RockStar and Sony to see if we can get confirmation.