Well in english I've generally seen the word spelled as pezhetairoi but I guess you might not be english What I was getting at (in a roundabout way) is that Klerouchoi in thrace would have been the macedonian/greek soldier settlers from Lysimachus's time or even before/after that time in thrace fighting for thrace to defend the land they owned. Macedonians would generally be better trained (pezhetairoi http://books.google.ca/books?id=YPqz...tairoi&f=false) but since they were macedonian/greek settlers, I guess they could just be klerouchoi instead because maybe they would have been influenced by the thracian culture in terms of armour as influence of original seems to have affected settlers to a large extent in general.
Also I believe Iphicrates imitated the thracians when creating those reforms , I need to find some sources too but I will edit them in To note a few things, one the word sarissa is not greek. It originally meant long spear and thracian horsemen were known to have also used long spears from the 5th century bc onwards. Thracian Sarissophoroi were extensively used by Alexander. Thracian Sarissa> "D.Head, "The Thracian Sarissa", Slingshot 214 (2001), 10-13" And also an interesting read on the reforms here http://www.ne.jp/asahi/luke/ueda-sar...hikrates1.html
Didymus "He (Philip) received his third wound during the foray against the Triballi, when one of his pursuers thrust a sarissa into his right thigh and made him lame"
http://books.google.ca/books?id=rR88jF6taekC&pg=PA20&lpg=PA20&dq=Thracian+sarissophoroi&source=bl&ots=gzgRpsPjs2&sig=ZFdgegUjqu5YvnPvqv2NKzj8WTs&hl=en&sa=X&ei=_pM1VJuaLpCXyATq-IFo&ved=0CEYQ6AEwCA#v=onepage&q=Thracian%20sarissophoroi&f=false
Europa Barbaroums interpretation of thracian prodromoi was this and I feel they studied thracian cavalry more than I did, which is why I included them as a source. Where I've looked so far it supports the fact that thracian cavalry used long lances and were the among the very best light/medium cavalry. (medium due to leather armour *The Thracians 700 BC-AD 46 >Men-at-Arms< by Christopher Webber and Angus McBride, 2001, page 5)
http://www.britannica.com/EBchecked/...kans#ref476014
Also with advanced metal working I am sure they would eventually be interested in armouring themselves more thoroughly with time. Rather than just cloth they would use at least leather armour ,which seems to be lacking since it was used, or with bronze/scale armour with the influx of wealth. As evidenced by the rich thracians eventual adaptation of the scythians technologically superior scale armour. In general I think they would at least be open to at least a hoplite phalanx due to the greek influence, although thracian influence on the Iphicrates phalanx suggests they would be more open to a macedonian style phalanx, especially considering macedonia was closer than athens along with all what I listed before. I see that even the scythians have a greek form of troop type. So it's sad you aren't open to this. Not only that but the thracians were noted to be able to form and hold a line in formation... as you said yourself "“Thracians defended themselves skillfully against the Theban cavalry […] closing their ranks in battle order as typical of their country” (Thucydides, Peloponnesian War, 30)" So they weren't just skirmishing peltasts who ran away all the time. If they had too they'd stand and fight depending on their current strategy/tactics according to each battle. I won't argue that they did not prefer to skirmish but I will say that they should be allowed access to the other units that they would have likely had at the time. e.g. a form of pikemen/hoplites.
I do notice that there aren't really any greaves being used, and that there are no shields strapped to the backs of horsemen either. And the thracians were noted to use shields among many cavalry who didn't at that time. And I wonder why there aren't many thracian helmets like the one above. I thought thracian face masks were used more than what's shown.
On this artwork for example it seems there is a face mask with a helmet or maybe I'm just seeing things, possibly a shield on the back too. Along with greaves.
Maybe greaves are missing due to this?
But I wonder why there aren't at least a few...
Also since it's bothering me a bit, that you might bring up that you think only thracian cavalry used sarissa's, peltasts were also known to have used them on foot. Hence the idea about Iphicrates reforms.