Hi Gav,
Well, as if Chinese weapons weren't esoteric enough around here, you have gone yet another dimension!!
What an absolutely fascinating topic, and since I know little on Chinese weapons.....and if possible, even less on these, I started doing some homework.
Most of what I found is likely the same ground you have already covered, which is that as happens with most weapons that defy the understanding of the west, these are lumped into the martial arts anomalies of the latter Qing period. This same unfortunate attitude which has been exacerbated by the theatrical Hollywood movies sensationalizing these themes, has led to some nominally shallow scholarly work concerning some of these weapons. It is claimed that these type hook swords may date to the Song dynasty and Warring States, but since no examples are included in contemporary armaments records as far as discovered, this can only be speculation.
It seems to me that much as with many martial arts, especially those using weapons of varying form, much of thier use is intentionally theatrical, and often may appear simply psychologically threatening. This is known to have been the case during the Boxer Rebellion, where these Chinese martial artists deliberately put on most intimidating performances before the forces of various of the countries present. The same elaborate movement exercises are used in SE Asia, Japan, India, and certainly many others.
While appearing theatrical, the conditioning and familiarity with the weapons would render any warrior or individual potentially lethal in actual combat, regardless if following regimented or scheduled movements or not, even for that matter if not even using the weapon form itself.
I think that probably somewhere in some lost references in a musty archive, there may well be some sort of reference to these, along with those of many of these incredibly exotic weapon forms of China. Hopefully lurking out there may be a scholar who has stepped far beyond the bounds of the shallow research we so often are faced with when it comes to these type weapons.
I am inclined to think there are.
All best regards,
Jim