It’s often reported that they require a turban as part of the observant faith. But all I can see in the “official” sources I looked about is that kesh means unshorn hair, and the turban is a traditional way to manage hair. Of course many use a less traditional turban if they’re younger or doing sports etc. while others in the modern era may cut their hair and shave. But for a devout Sikh, are they considered sufficiently observant by other Sikhs if they braid it or something?
Wiki has this:
The patka, as seen on that pic, is no less traditional than the turban.
Yeah. The OP may just have meant that the patka looks less like what westerners traditionally consider a turban than the pagri/dastar does.
That was one of my “yes it is required” cites. The Wikipedia page on kesh and sikhs.org suggest that uncut hair is sufficient. Sikhiwiki seems to do so too.
Correct. It just seems that patkas aren’t as good at holding adult-quantities of hair, so are seen more on younger people, but maybe I’m wrong.
They hold adult hair just fine. A friend of mine from college called it a “sports turban.” 
I knew a guy that was a Sihk in high school and didn’t shave and wore the turban. We had a battle of the bands one time at school and he came with out any head gear on with his hair sort of braided but otherwise loose, I had no idea it went all the way to his feet.
The page you cite claims that a turban is required but provides no citation for that claim. I’d like to see a source that Sikhs themselves would accept as authoritative—that is, either their original scriptures or commentary thereon by a guru.
The Kesh, which can be loosely interpreted as “uncut hair” is one of the mandatory five Ks of Sikhism. We Indians are taught that in school ( I am Hindu ), across India, whatever faith we profess.