I don't know if anyone has written about this, but I found that you can have customized home, away, sunday and classic uniforms for every individual player, just like you can have custom practice jerseys.
As a test, I copied a patch of Toronto's home jersey files (tohome.fsh and tohome_num.fsh) to Kevin Garnett's custom art folder (render/xplayer/kegarne). I then renamed the files to just home.fsh and home_num.fsh. When I played a home game with Minnesota, Kevin Garnett was wearing the Toronto Raptors home jerseys, complete with his name and number, while his Minnesota teammates all had the normal T-Wolves home jerseys.
Obviously, the same method can be applied to creating custom away, sunday & classic jerseys for each player. But you do have to keep in mind that the jerseys you create will stay with that player no matter what team he plays for. For example, if you make a custom version of Minnesota's jerseys for Kevin Garnett, he will wear those jerseys on any team he's traded to. And players that are on regular NBA teams as well as the All-Star teams (like MJ, Gary Payton & Shawn Kemp) will wear whatever custom jerseys on all their teams as well (although you can get around this by editing the players.dbf file).
Anyway, this seems like it has several uses. I think it's the only way to have the player's number on their shorts. And I was thinking of using it to make a patch for AI that would have his jersey untucked, like it was in last night's game. Or you could make any team be like the all-star team and have different team jerseys on each player.
Like I said, I don't know if this has already been mentioned somewhere, or if someone is already using this method, but I figured I'd post this in case anyone doesn't know about this.