KDE 3.5 is a very misterious KDE release. When the project is moving to version 4, which will be based on Qt 4 library, it's hard to say how much time it will take.
CVS version screenshorts were posted. From a post on kde-core-devel it looks there will be KDE 3.5. When? Hard to say. It probably depends on Qt4 and KDE4.