Creating a new pressure pad is exactly the same as a switch: you just setup a mesh with an "On" animation and give it the controller type "PressurePad". Easy.
I did trip over a few content pipeline issues while doing this one: I had to setup the exporter to handle skeletal animation not centred at the origin, I needed a way to tell the exporter whether animation that moved things should be considered motion or not (e.g. "Walk" actually moves the character in the level, while "On" doesn't move the pressure pad, it just changes it's position for a while), and I had to work around Maya requiring each animation clip to have a unique name (if the switch has an "On" animation, the pressure pad gets "On1"). Nothing I couldn't fix up on the train on the way home though. Here they are:
The up/down action is pretty subtle, and nearly impossible to see in a series of static images, but it feels pretty good (even if I do dislike the prototype mesh I knocked up - unlike the switch, this one isn't growing on me).
I was dreading handling the physics for this one: if the pressure pad actually moves, it will create hard "steps" in the terrain which will catch blocks that are being pushed on and off the pressure pad. I do have an action item to go back and try and work out how to stop blocks from catching as easily as they do, but given the pressure pad requires a visible step, tweaking the physics wouldn't be enough anyway. The solution turned out to be simple: don't use any moving physics at all. Just having an animation which pushes it down and brings it up looks just fine (and it's strangely satisfying to walk on and off the little things and see them depress).
I even added a "Threshold" setting, so you can tell the pressure pad how much weight needs to be on it before it activates.
Now ... what to do next? I've been putting off "enemies" forever, as I haven't come to a firm decision either way on whether to have any combat, how to handle health and death etc. A moving platform/lift possibly? Here's where I need to be disciplined and ask myself "what is going to get me closer to a playable game?". Unfortunately, years of tinkering have convinced me I am poor at answering that question honestly.