I suspected as much, but I think your answer is as definitive as anyone is ever going to give, so you've added knowledge
From what you have in front of you, do you think if you had the "stalk section" from a MFSW switch set (withOUT cruise), and put it together with your "cruise but not MFSW" you could make one that gives you all the things you need? I have the old one from my car (MFSW, auto wiper, rear wiper, without cruise) that you could have for postage if it helps (I was going to sell it, but never got around to it, and cant be ar$ed). Add your clock and your cruise stalk, and it might give a complete cruise unit? If you want, I can take some pics to help see what its got, and whether you think it can be used to assemble something useful.
Or, following my own logic (if indeed logic is the right term ), could you just add the extra cruise stalk from the unit you bought to your existing unit? Do the stalk switches go through a connector rather than the clock (slip ring), as they dont need to turn with the steering wheel?