I think it's obvious that Nokia's after QT as a possible replacement for S60, possibly on Symbian as well as Linux.

However, Intel and Canonical are both using Hildon for MIDs and Ubuntu Mobile. I don't see Nokia switching Hildon from GTK to QT without forking it; just because Nokia now wants to use QT doesn't obligate Intel and Canonical to join in. Nokia doing that (assuming it could even be done) would also cause Maemo upgrade pains, which they've already caused a lot of.