They at best could only stock pile the players without a NBL contract, and the guys who are worth 4-6 points and can get a roster spot somewhere are not going to give that up to be training fodder and rotated.
But yes if you can fit it in under your teams salary cap, and there is a player like Trueman available, why not have him as your 11th man and rotate him in when you see fit. But obviously all 11 players need to fit under 70 points, many teams would struggle with that, both the Wildcats and 36ers definatly couldnt do that as they only just scraped their 10 man rosters under the 70, both have 1pt players on the roster to allow for the other 8-9 guys they have, and the player has to agree to take a role like that, ie not have a full time contract offer at another club, or have another career that they wont give up to be a part time basketballer. So easier said than done.