Zeus, if you read your licence it tells you a lot of stuff. One of th ethings it says is that you amy only advertise reptiles through a herp club. It also says that reptiles may not be sold through pet shops.
NPWS knows for sure that herps are sold through web sites like this one. Anecodely, they have stated that they see this site (and others like Herp shop) as a "herp club" so to speak. So they have no trouble with herps being advertised here (or on Herp Trader). Their main issue is with sites like Petlink that are not herp based.
Of course, they are aware that people sell on petlink, and have done so for many years now. They have taken no action. Although this is a question for the lawyers amongst us it is reasonable to assume that they see this as acceptable behavior short of them issuing a practice statement or something similar saying that it isn't.
and yes, you can buy from interstate pet shops (or anyone else for that matter) providing you have an import permit and they have an export permit. Just imagine trying to take a turtle across the Murray River!!!
I also understand that the NSW system is about to undergo a major overhaul. They are tight lipped but initially I think they will be changing licensing to be based around the number of herps you keep. So a keeper with only 1 herp will have a different licence to a person like me who has, say 3 herps.
and then there is an election next March that may change all that again.