I updated my copy of the qt-at-spi package to version 0.1.1 and verified that it compiled successfully. It was necessary to install QT 4.8 development packages from Experimental; the build dependencies in the Debian control file should perhaps be tightened to specify >= 4.8. I haven't installed a test application, so I can't confirm that it works - only that it compiles and installs the shared library apparently into the right place.