According to the intertubes, Microsoft is forging ahead with Halo using a new internal studio. Forming the team are Ryan Payton, formerly of Kojima Productions and the producer of Metal Gear Solid 4; Corinne Yu, former technician at Gearbox; and at least two former Bungie employees: writer Frank "Frankie" O'Connor and animator Nathan "bentllama" Walpole.
This formation puts Bungie's independence in a bit sharper contrast. While Keep It Clean shows that Bungie isn't done with Halo, it is no longer the only thing they are working on. While there were always supposedly other projects in the works while Halo games were in production, none ever reached fruition, and the Halo projects typically consumed the studio's entire attention come crunch time.
That Bungie's Halo project is billed as "Halo 3", indicating an expansion rather than an entire new game, indicates that their commitment to the title will be somewhat less in the past, giving room for new developments.
Presumably the new studio will be 100% devoted to Halo. So the question will become: will fans be just as interested in Halo games not made by Bungie? Will these games be FPS, like the Halo series to date, or something else? Time will tell.