Jesse did confirm today that Chinese Fast Wrestling, or Shuai Jiao, is Tai Chi fighting.
Scott, what Jesse confirmed was that Shuai Jiao is 'Chinese' wrestling or fighting not 'Tai Chi' fighting. Shuai Jiao and Tai Chi Chuan are both part of Wu Shu, but Shuai Jiao is part of the external arts, while Tai Chi Chuan is part of the internal arts.
It seems the natural evolution of free-step push hands is Shuai Jiao.
Scott, What I read about Shuai Jiao is that it is a traditional Chinese fighting using 4 techniques, Da (hand boxing), Ti (feet boxing), Na (grab...), and Shuai (projections, sweep), which origin can be traced back to 1600 years BC. I don't think it can be an 'evolution' of push hands (or I misunderstood what you meant?)
Yes I know they are mixed in that video. Originally push hands never considered as something for competition, but rather a training method. Modern time it has become a competition which for the most part looks as wrestling. Look at this for example
http://www.youtube.com/watch?v=phLBusl2BRA
Andrey, I agree with you, at a competition level, it all seems like some 'Chinese wrestling', and the four principles, Zhan, Nian, Lian and Sui, which I'm trying to understand and (without much success) to train in Push Hands don't seem very 'subtle' to me at this competition level.