Some time back this is something I was using myself, but I can't for the life of me come up with any useful results in searching.
There was something, I believe it might have even beet a UI mod (although they probably have removed controls like that in the UI API at this point, if it were) that removed the loading screen overlay, so a tiny loading graphic would be placed, and you would see the initial world render, and it would cut sit-and-wait time considerably.
anyone have any clue whta I'm talking about?