I'm in a class on the subject at CMU, so I should be able to find out. What you said about Asimo is not quite true; for instance, one guy here at CMU wrote some code that took Asimo and constantly replanned in real time, so that he could respond to various changes in the environment dynamically.

Here, for instance: http://www.cs.cmu.edu/~Joel/footstep/videos.html#ASIMO

It would help to know more about exactly what Dexter is doing, so I can find some similar stuff. There is a large amount of literature on the subject.

Also, you note that Asimo's floor has to be hard and flat-- generally true, but also true for most bipeds, which seems to include Dexter. Can Dexter really deal with irregular terrain? How irregular can it be? An interesting question is how to get a biped to walk on *really* irregular terrain, like boulder-size.

Sony claims that Qrio can respond to outside pushing, as here:

http://www.plyojump.com/movies/qrio/sdr-4x_recoverfromfall.mpg