Here is an interesting bit of news for Qt developers. RIM announced the Native Open Source Components Initiative. The idea is that commonly used Open Source Libraries will be used in conjunction with the BlackBerry Native SDK for Tablet OS. When looking at the General Libraries, Qt is mentioned first in the list. Further information about Qt reveals that Qt Quick is included in the initial port. So, at least in theory, is should be fairly easy to port existing Qt apps from, for example, Symbian, MeeGo or Maemo to BlackBerry PlayBook.
Source: BlackBerry github