Ok, so far, I see some limitations. Desktop widgets can not be resized in QML, because they're created in a fixed size, and can't resize afterwards unless it's made a button for it, but still it'd be fixed.

What I make will be able to play both audio and video, so no worries about that one.

Ok, after some consideration, video won't be possible with QML. There is a problem with the Video-element, so.
But i did make a freakin' nice GUI for the audio-player! It's got smokin' hot QML-effects for sure!
QML is sent from heaven...