Short summary: Don't use Samsung's Unified Driver (which worked OK on SuSE). The scanner works plug-and-play with Skanlite (not in Kubuntu default install, btw), and the printer works after adding it in CUPS without proprietary drivers.
Unified driver: See the openSuSE version of this post for more details. There is also a fairly epic discussion on the Ubuntu fora about Samsung multifunction devices, the Unified Driver and its problems with Lucid.
First impression: starting the install script actually resulted in a GUI installer (although a pretty ugly one). This had failed on SuSE, but, actually, I prefer a decent console walkthrough with some informative output. I restored the original /usr/bin/lpr and tried to print a test page both from the installer and from CUPS, which got me only a "mfp failed" error message in CUPS. Ultimately, I just ran the Unified Driver's uninstall script and installed the printer over CUPS' web administration interface (SpliX driver).
Seems I've been lucky - according to the forum discussion, it can get pretty complicated with less basic machines (e.g. colour, duplex or network printers).