No nothing has been confirmed, however, director Rich Moore has been speaking about possible story ideas for a sequel. He has mentioned he would like to have Tron and Mario make appearances.
Tron would be a good possibility since it is also owned by Disney, and I would love to see Mario show up in there as well. They still can go several ways with a sequel, but I just hope they don't ruin the first one with a bad sequel. If they did it right though, it would be awesome.