Love that in the US close combat video at about 4.30, after knocking his opponent to the ground, he stops to adjust his hat before putting the boot in...
Also... to justify having posted that comment-
Jack Dempsey vs. Bill Brennanhttp://www.youtube.com/watch?v=mFxcNfXMA60
There are several Dempsey fights on youtube but this seems to be one of the best and closest... lots of very low slipping followed up by work from the clinch which seems to be very characteristic of the style.
Old Muay Thaihttp://www.youtube.com/watch?v=xAtgyIbkRaw
Not strictly HEMA (except in the sense which would be opposite to HWMA... but let's not go there...). Is interesting though... It's only a short snippet (with an annoying trailer in the middle c.2.10-4.20) but it shows a style that appears as different from modern Muay Thai as Dempsey is from modern boxing.