This bug is gone after an upgrade yesterday. I'm still at 0.27.1-1, so not sure which package ended up fixing this. But Xorg.log now shows:
[ 49.791] (II) config/udev: Adding input device Lite-On Technology Corp. ThinkPad USB Keyboard with TrackPoint (/dev/input/mouse2) [ 49.791] (**) Lite-On Technology Corp. ThinkPad USB Keyboard with TrackPoint: Applying InputClass "DisableTrackPointScrolling" Ross
