To build qt app for Maemo 5, you have 4 ways to do it:

1st: Install scratchbox, Maemo SDK and in SDK install libqt4-dev. Copy your project to somewhere you can see it in scratchbox and build it inside scratchbox.

2nd: Install madde (you can find guide for it somewhere). It works in Windows and Linux.

3rd: Install Nokia Qt SDK and during install select Maemo Toolkit (i think it uses madde too). Works in Windows and Linux.

4th: Install Nokia Qt SDK and select experimental tools and Qt Remote Compiler. You need Forum Nokia account but you dont need any SDKs or other tools installed than QtCreator. Works in Windows and Linux.

And to the topic:
I use Maemo SDK in Gentoo and got it work easily.
Best way is to install scratchbox from distros own packagemanager and Maemo SDK from gui-installer

You don't need to specify project to be Maemo project. Same project should work for S60, Linux, Windows, Mac and Maemo.