The Maemo-specific WA_* attributes in Qt, originally documented in Qt 4.6 docs, are gone in the new 1.2 SDK !
They have even been removed from the docs!

A few of those attributes were essential, like the one to make stacked windows -- how are we supposed to do them now?

I have updated my SDK but I can still use WA_Maemo5StackedWindow, WA_Maemo5LandscapeOrientation, and WA_Maemo5PortraitOrientation etc. as well as the previous version, 4.6.2~git20100212-0maemo1.

Weird :/
I have to say I use Qt through the python bindings, but it was working before and now it doesn't. I guess the PyQt mantainers need to do some compilation magic.

What I found more worrying was that all references to those attributes (and all mentions of Maemo) have been scrubbed from the online docs at doc.qt.nokia.com/4.6. They are still available in the version at qt.nokia.com/doc/qt-maemo-4.6 . I'm sure in the past they were the same, so I freaked out a bit.
But if you say they are still there, I can relax

I presume you are using PyQt from Extras, which is compiled against Qt4.5 (which does a few things differently than Qt4.6). PyQt compiled against Qt4.6 (thus supporting all of it's constants and classes) will follow PR1.2 closely. I had all the stuff already tested with the libqt4-maemo5-* and it worked nicely, though as you say, there seem to be some changes under the hood, not just simple renaming (hence I will wait for actual PR1.2 to be released before I push the Qt4.6 version to Extras-*)

Great
BTW, do you plan to build PyQt for MeeGo once we get a build with Qt on top?

Absolutely. The only question is how many extensions will it have to vanilla Qt, as those will probably not be supported until MeeGo gets a stable release.