For fans of the oft-overlooked taller plumber, rest assured: Luigi is returning in another of his own titles on the 3DS later this year. Luigi's Mansion 2 will have not just one, but several new mansions to hunt ghosts in. From the looks of it, they'll all be differently themed. I think I see an Egyptian tomb in there, so perhaps there will be some mummy-ghosts to encounter.
No news on whether or not you'll be able to choose different models of vacuums, but there's always time for that later.