If anyone is still interested, these things are now available here in Japan. I picked up a couple at Yodobashi Camera in Osaka this week. No, they don't have ultrasonic printed on them. They are thicker than the old side pinch type, but not enough to make a difference (i.e. they still fit in my bags).
I do use lens caps at times (when moving by train to different location, in museums that don't allow photography, etc.). Guess I'll see if the center-pinch types were worth the 850 yen price in the next few months.
