I've now generated 1500x1500, 1800x1800 and 2000x2000 versions, both USGS grayscale-relief and color-coded, in upright, Newtonian and star-diagonal orientations, for a total of 18 maps. I'm not entirely happy with the grayscale-relief color scheme--the yellow labels don't stand out nearly as nicely as I wish they did (maybe I need to darken the shadows behind them? or switch to a different color?) I've also moved this off my home server to a proper host:
http://pruss.mobi/moon.html

You may notice that the actual files have more pixels than, say, "1500x1500" indicates. That's because the "1500x1500" refers to the moon image itself, but labels stick out past it.