A friend recently lent me a book about a self-defense system called "Guided Chaos", which was developed by a police officer in New York City. (
http://www.attackproof.com/)
I was surprised to see much of the philosophy and training methods are similar to I Liq Chuan (perhaps because both systems utilize Tai Chi principles?):
For example, Guided Chaos is based on the principles of "balance, body unity, looseness and sensitivity".
The book also discusses the importance of concepts like flow, stickiness, maintaining a strong stance, etc. They even have a partner exercise called "Contact Flow" that looks a lot like spinning hands ...
In fact, the only major difference I have seen so far is that Guided Chaos advises against squaring off to the opponent (i.e., hips squared toward the opponent), in favor off standing at an angle in order to minimize the target area on your body. Guided Chaos appears to be quite popular among law enforcement and ex-military.
Peter