I thought I'd open a new thread on the subject of the clothing of the various armies depending on the time in the war.
I deal mostly with Trans-Mississippi Arkansas - 1862/3 and my sense of the clothing for the troops was mostly a "Feast or Famine" situation. Mr. Bergeron I think rightly points out that some of the items used in the TM came through or from Texas/Mexico. I get the sense that this was expecially true in the early war.
However, in Arkansas in 1862/3 (The Hindman Era) I think that there is considerable evidence that they looked mostly eastward for supplies, rather than south. Hindman directed some officers to scour the depots in the east for whatever they could find upon his arrival.
I have not seen similar directives to go to Texas - (while of course they could be there - but I haven't seen them)
Marmduke's order book does clearly state that prior to the Battle of Prarie Grove Arkansas - that enough "English Army Cloth" had arrived to make about 10,000 uniforms - and that tailors needed to be detailed from the ranks to make them up into uniforms.
Buttons, and other oddball items have been found by diggers from their camps to indicate that some uniforms made it in from back east. I have even seen a NC button coming from a reb camp of the period (Where no NC troops ever were). Eastern tinback "block I's" are very rare - but not impossible to find. I would guess that the scavaging of other depots yeilded a very wide range of leftover items that made their way to Hindman's little army.
After the Prarie Grove fight - I think that a Union General - Either Blunt or Herron - remarked that the dead confederates on the field were well armed and in new uniforms.
While they did have some "rag tag" units and periods of time - I do think that they Arkansas Trans-Mississippi did a pretty good job considering the situation they found themselves in in Mid to late 62.