It was not on the track, but once at the World Mtn Running Championships I noted the team from Poland had white cotton sleeveless tops (think underwear/wife beater type ribbed cotton shirt) with a simple small Polish Eagle patch/logo safety pinned to the front of it.
I kid you not.
At least they had matching singlets and uniforms which was more than some countries had (Mtn running at that time was not attracting much attention or sponsorship $).
Being partially of Polish descent, I had to have one so I traded some things for one of those. One runner was so proud of his that he would not trade it away.
Some of those Polish runners raced and placed well in those.
This totally reinforces the idea that the best singlet may not be the most functional, attractive or expensive, but the singlet that inspires you the most.