Progamerz has put up a short FAQ on the Halo Editing Kit with answers from Gearbox programmer Hellface. The release of the kit (as with the 1.04 patch) they say is up to Bungie and Microsoft now, and not Gearbox. Thanks rapture via Louis Wu of HBO. Incidentally, most of the information is regarding stuff that either won't work or hasn't been tested, namely moving geometry, variable media height, damage-causing media, etc.