I've toyed with the idea of eventually training just the SF position and making some uber SFs, especially for my country's NT/U21 teams. SFs seam to be a relatively hard position to train since they are in that strange limbo between big man and guards, and don't necessarily have nice training options set up. I also think that a good SF might make a nice chunk of change for the team that trains them well.
Of course, this is only my third season in the game, and could be (and probably am) way off base here :)