Shivering Isles could be the first and last full expansion Bethesda releases for Oblivion. The developer has said that Shivering Isles is "the only expansion we have planned".
Speaking to Next-Gen.biz, Bethesda executive producer has explained that now Shivering Isles is out the door, full focus has switched to Fallout 3.
"We have pretty much everybody on Fallout 3 right now", Howard said. "It started off kind of small and then we add people to it and now the expansion's done, all those people have come on to Fallout 3".
"That's the thing we want to focus on right now, so I think I'd be surprised if we do another expansion", he added.
When asked about the possibility to Bethesda farming out development of future Oblivion expansions to other studios, Howard answered that the studio is "really getting into the stuff we're doing with Elder Scrolls and Fallout and I guess we're shy about having someone else start making content."