We've just released a big set of Teutonic Knight high commanders for our later 14th century Medieval range of 15mm. It has four leaders and two standardbearers. One of them depicts the Hochmeister as he's described at Grunwald, but could equally be other Grand Masters for the late 14th to early 15th centuries. Available now:
http://khurasanminiatures.tripod.com/late-fourteenth-century.html (it's about 3/4 of the way down the page)