Nasa.gov may have stuff like that. You may have to dig around for it. They have some resources for CG artists, but I don't know if they have anything like that in that section.
Yeah...supposedly there are lunar dem files out there on different scientific sites. You have to be a huge science geek to know what you're looking for and most of their sites still look like something from the year 2000, lol. This site works ok...I got some good results using the shaded altimeter data in zbrush...Wish I had this when I was working on my Clavius base craters..maybe I'll redo that part one day lol
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http://www.mapaplanet.org/explorer-bin/explorer.cgi?map=Moon&layers=moon_clementine_multi&west=-180&south=-90&east=180&north=90¢er_lat=0¢er=0&defaultcenter=on&grid=none&stretch=auto&projection=SIMP&advoption=NO&info=NO&resolution=2