The Qt 4.7 Tech Preview has been released a while ago, and we've gotten a lot of requests to package it for the N900.
Read on if you want to live on the bleeding edge :)
The good news is that the Qt for Maemo 5 repository got a 4.7-fremantle branch that contains a relatively up to date Qt 4.7 with all Maemo 5 changes, the even better news is that we've updated the Debian packaging files to support the new Qt 4.7 features (namely QtDeclarative), and the best news in this already far too long sentence is that we've created packages for your convenience at http://chaos.troll.no/~harald/qt4-maemo5-4.7/.
To download all the *.deb packages from the page above, you can use wget: wget --accept *.deb -e robots=off -r -nd -np http://chaos.troll.no/~harald/qt4-maemo5-4.7/
To install Qt 4.7 into the Scratchbox based SDK (warning - this will overwrite the Qt 4.6 in /opt/qt4-maemo5):
dpkg -i *.deb
On the device, install all the *.deb packages except for the *-dev and the *-dbg ones (debug symbols on the device are useless when remote debugging).
To uninstall, run:
apt-get remove .*qt4-maemo5.*
Disclaimer: This is a tech preview. Please only install if you would like to contribute to Qt 4.7 for Maemo 5, or if you want to play around with the latest Qt 4.7 features, knowing that all new code might change and you might have to toss your prototypes.
The road ahead: Once the PR 1.2 release of Maemo 5 is out, the Qt 4.7 packages will replace the Qt 4.6 packages in the extras-devel repository. The stable Qt 4.6 will reside in /usr, the unstable (and optional) Qt 4.7 in /opt/qt4-maemo5.