Benjiboy - both the x570 and x700 have it. The x700 was the first Minolta that did. The flash I have was made specifically as a piece of this system. I've used them together, on camera, for a few rolls and am trying to figure out how to get more flexibility and better quality light without carrying around a lot of equipment.
You're probably right about the Pentax, though. But I'm not planning to use it for this, it was just an example of the hot shoes being different.