I'm doing pretty good steps with the tileeditor.
Here's a video in which you can pretty good see what
the current state of the editor is:
(I recommend to watch it in fullscreen,though)
It is possible to create a new tilemap and to set a few properties (Mapsize,tilesize,name and the tileset) for it.
The next step would be to implement the possibly to draw tiles on the map.
You'll hear from me again if that's done.
Oh and by the way:
Qt is goddamn good library!
I absolutely recommend it for Gui programming!