I faced the same problem gui sdk in linux was not a good idea.

First I used scratchbox on debian squeeze. I could setup everything fine except debhelper. But I wasn't able to make proper packages and send to autobuilder.

On my laptop I running a win7 and need to make some Qt apps for windows. So I decided to install the nokia Qt SDK 1.2.1 (offline version). It was easy to install and easy to make a deployment. The only thing was that you need to change your debian/rules file to work with the autobuilder and add a custom step to create dsc;tar.gz;changes files for the extra assistant.
Now I feel really bad because I develop for linux on windows.
Sometimes it is really frustrating to invest so much time to setup a crosstool compared to the time for writing a small app.