The advent of modchips and hardware hacks for the Xbox have meant even more interesting things have been found out about Halo in recent days and weeks-- even things that fansites have been discussing for a long time and thought were impossible.
Louis Wu at HBO brings word that BOLL and Phforslayer have colluded to replace the first warthog in the level "Halo" with a Banshee-- which is flyable, something long thought impossible on that level. Not to be outdone, BOLL went ahead and posted screenshots of the Engineer model in HBO's forum, in engine-- again something that long was thought not to exist in the game as shipped. That same post has screenshots of Ghosts on Silent Cartographer.