MADDE is now a TECHNOLOGY PREVIEW. It is not official supported way to develop for Maemo, only Scratchbox is.

And YES MADDE supports Linux (32/64 bit versions), take a look on first list on http://wiki.maemo.org/MADDE .

Integration of QT Creator and MADDE is still not official - you need to use Qt Creator version >=1.3.80 witch is not stable release. 1.3.81 ~~ 2.0.0 alpha :P This only way to give something to developers working on Win and Mac, they don't have native support for Scratchbox. I think MADDE+Qt Creator will be better way to develop apps for Qt mobile platforms on all supported host platforms, after PR1.2 :P

You can try to install latest QtCreator (from QT ftp) and MADDE and make them work together. It will have the same support, same stability as on Win and Mac.