Some time ago you could make a MPQ file and load custom models into the game, at that point the TOS made this bannable offense and you'd get banned if discovered by warden.
Today it's limited by the game itself, you'd have to hack/modify the game to make it work and warden would find that out at some point, and as far as I know, wowinterface do not allow executable so chances that someone releases something against the TOS is very very slim.
This brings me to a second question to Cairenn; why is the Leatrix Latency Fix allowed to post a exe? The vbs I got, but the exe is compiled. Nor are the sources available anymore, so I think you should look into it. I know Leatrix is a nice guy and I can trust him, but still I think more would feel safer it it was readable and not an exe.
Not to mention lack of consistency!