In Lanna I worked with staffs of different length although the difference was small, around 46-50 inches. There are shorter sticks too like the Kom Faeq but I have never seen poles like those used in wing chun. The longest weapon I saw in the Thai arsenal was the spear.
I have seen in the FMA, their staff is usually just under head height, kinda short for a staff IMHO. I have seen early in the ABA (Modern Bando mind you) that the long stick (Dhot) staff was typ about the height of he practitioner if not 2-3 inches longer, and this was for the 4 winds, 4 corners, the horsemen, the Pilgrim and even the Dissident Son staff forms.
But I had seen in the Horsemen staff form, many liked a longer staff to show how the principle of the form was to show a man on foot fighting off riders on horseback. I was told that in the ABA, the 4 winds runs thru the 4 corners thru the horsemen as 1 form, this was called the Footsoldier Vs. the Horsemen and some have abbreviated it to the Footsoldier. Depends on who in the ABA you talk to and what era they were trained.
Even now I have seen that the ABA uses an approx. 7' -8' or a slightly longer staff (Dhot) for all those forms now w/ a red cloth attached as decoration defining a spear tip end. This longer staff affects the begining staff chamber as I have learned so to speak. When I started in the ABA Banshay forms, one staff for all at head height. When walking we were to carrying it against our shoulder securely (Not unlike how a soldier was to carry a rifle) after our salute we turned the staff over under our arm pit behind us to start our forms sequences. We had to keep it as vertical as possible and not knank the floor with it.
Now with the longer staffs (Dhots) the staff is too long for this and when the staff is tucked away so to speak, they angle the spear tip end out near 45 degrees and when they stand at ready the staff is not held w/ feet together vertical on shoulder but w/ feet apart none spear tip end on ground at side w/ tip leaning away to the side near a 60 degree angle. This is top accomidate its length.
Many other systems I have seen such as Vietnamese staff work looks very chinese like (And there are a few Vietnamese instructosr in the DC Metro area I have seen, never been to Vietnam) ranging from a simple staff to the flexible spear to even a Kwan Do like staff/weapon. Koreans systems typ. use a head height staff and so do Okinawan and Japanese although there are variations like a Naginata etc...and other spear like weapons.
I got long winded not to be opinionated but to show how diverse systems can be in their prefered staff length work. What ever system someone trains in, it is up to their Instructor to define desired staff length, even if whille in the west (United States etc..) they may alter staff length to fingerprint themselves as different or simply (In earlier years) quality staffs at differing lengths were not easily available. Regardless I prefer a solid head height staff or alittle longer, but I hate those narrow toothpick staffs, they dont hold up except for demoing flash.
I trust many hear also have their opinions, just wanted to express mine.