Hello! --with-arts is now default, so I have added arts to IUSE... Best regards, Andrew.
Created attachment 38465 [details] ebuild
OK. I have found that scrollbars are badly positioned (by one pixel). Here is patch to fix this.
Created attachment 38485 [details] ebuild
Created attachment 38487 [details, diff] patch
Created attachment 38608 [details, diff] slightly better patch
Created attachment 38795 [details, diff] much better patch
Have you compared your work to what's in the upstream CVS now? http://pdx.freedesktop.org/cgi-bin/viewcvs.cgi/gtk-qt/gtk-qt-engine/src/qt_qt_wrapper.cpp?rev=1.40&view=markup If upstream still needs these fixes, I encourage you to submit it directly to them.
Brad committed this, works well.