One cross-training experience that I believe is being overlooked is the study of Russian Systema. Systema originated in the 10th century and was passed down orally for hundreds of years until the 20th century when it was suppressed by the Communists. A version of the art is now taught to Russian military units and there is active work on reconstructing the original version. A full history can be found here:
http://www.russianmartialart.com/main.php?page=history
Their training methodology is based in Christian Orthodox philosophy and stresses the importance of psychological and breathing techniques. The essence of the art is to allow an opponent to resist in such a way that it brings them into position for a throw or strike. The strikes used in this context have a very fluid motion to them. Many of the techniques used are almost identical to Passchen's methods.
http://www.youtube.com/watch?v=MWo1HphOsvo
