Is it possible run Transmission daemon and Qt/GTK GUI at once in sync?
Solution 1:
I am happily using Transmission Remote GUI for few years already. It is not exactly the Qt or GTK GUI but it works on multiple platforms very well. The package is contained in Ubuntu. Just install the transgui package. On the project site there are also current binary packages which run on Ubuntu.
Another option is to use transmission-remote-gtk which has a PPA. Unfortunately I have no experience with this one.