Found it. For anyone who's wondering, it's behind the fan blower on the passenger side, tucked away where you can't see it and can't reach it. And if anyone's interested, the central locking module is above the glovebox. Taking out either of these modules requires the entire dash to come out.
Umm, just out of interest (maybe Teddy would know or have access to knowledge?) my Camry has some of the plugs required for the cruise control. Namely, there are plugs to plug the cruise control main switch in, there are plugs to plug the actuator and vacuum solenoids in. But there are no plugs for the control unit or the brake switch. Any idea where the wires from the plugs that are there go? It's almost as if Toyota started putting the cruise control wiring in, and then halfway through decided not to finish it... Oh, also the set/resume switch is on the window washer stalk, and they appear to be interchangeable. Haven't checked if the body loom has the required wires yet though.
I'm probably going to end up custom wiring the entire thing, but if there is already existing wiring to tap into it would make life a lot easier.