I'd say Yes were pretty pogressive right out of the gate. On Harold Land off their debut album from 1969 you hear the same type of structure they used later in a much expanded form on the side long title track from Close to the Edge. Also the closing track off the first album, Survival is very similar to bits of Perpetual Change and Heart of the Sunrise (both recorded in '71.)
Survival;
http://www.youtube.com/watch?v=jAymX34mwqU
I didn't see early Genesis (1967 - 1980) on your list either. Their stuff from when Peter Gabriel led them is especially good. It was very influenced by The Nice, King Crimson, Procol Harum and Yes.
King Crimson were a vital band in late 60's and early 70's Prog rock. They both influenced and intimidated alot of other bands in the scene.