That's an interesting bike. Not a CroMo frame, however, as the tubing decal on the down tube says, "High-Tensile steel tubing." That would place it as entry level, but it looks pretty darn clean. You might be able to track down more info at the Miyata catalog site:

http://miyatabicyclecatalogs.blogspot.com/

Or try the Miyata group on Yahoo: http://groups.yahoo.com/group/MiyataSpecTour

Neal