Shattered Kingdoms

I'm pretty sure not all merchants offer gear of differing sizes, but what is the command to buy smaller/resized gear if they do. The merchants all list everything as medium.

If they only list medium armor that is all they sell, unfortunately. You would have to head to the tailor/forge to get it resized.

Yeah, it'll list the small size if it is (or whatever size it is). A few shops (the Teronian newb shops are the only ones that come to mind right now) will switch the inventory to your size when you walk in if you give it a sec. Otherwise, find your local forge/tailor/sorceror.