The Sony Clickpad support comes down to touchpads that have one physical button that covers the entire surface of the touchpad with virtual button areas painted onto the touch area itself. It's rather different from the Apple-style touchpads and thus a set of eight patches to support them.
The interaction model used for these touchpads with virtual buttons is implemented in a similar way to Microsoft Windows' support for them. Implemented is moving the cursor, tap-to-click, tap-and-drag gesture, left and right virtual buttons, dragging, insensitivity to bad clicks, and two-finger scrolling. Not yet implemented are zoom gestures.
Those with such Sony-style touchpads and are interested in the evdev-touchpad patches for Wayland's Weston, they are currently sitting on the Wayland-devel mailing list.