I doubt very much whether you'll have a non-ose version of VB in the debian repositories. Debian's philosophy is strictly open source or no go.
I'm using the squeeze PUEL version from Oracle on my wheezy machine. I do vaguely recall having to install Qt stuffies when I first installed the Vbox though.
Agree on the -ose thing.
Yes, it does have some qt dependencies. My qt stuff was preinstalled in the distro, think it's from VLC maybe.