This came up a few months ago. If I remember correctly, somebody mentioned writing a script to delete demos from the models folder from the cards one doesn't own. All well and good.
Then one can set the carousel to only download demos of your choice. (ie: turn off automatic download of demos).
Sorry but I don't remember if anyone wrote a script to do the first part. (Jump in here if you did!)
I don't see this as a ***** concept. Totem are in the business of selling cards and need to keep their products in full view of their clients. Any card a member doesn't own yet is a potential sale. I realise that as our collections grow, the choices dwindle so we have to put up with a fair amount of repetition. Once a member owns every card to date then the carousel remains empty until new cards are released. A few suggestions were made to keep the carousel interesting but I don't recall anything being done about it.
So, to answer your question, yes it can be done either by a script or deleting demos one by one manually.
Personally, I don't worry about the repetition. If I don't like a girl, I don't buy her. Just skip to the next girl or do something else. No big deal :)