The best resolution NED elevation seams to be at 30 m resolution - which is probably why I did not do PR or VI along with the state mapsets. Check the .img file at cloudmade.com - it may be limited to outline and road data.
When did you need this?
----- Contouring 30m for VI looks passable.
I have not done much testing with 90m SRTM data - somewhat different in VI, but may be usable; too me it does not look to usable for NA as it appears to over- and under-shoot the coastline and has many dangling contour lines; may be a projection isssue, but to me it looks like it is too widely spaced data for a small island to make an adequate contour map.
----- Test run with Census data and contours gives a 1Mb .img file. Some features in the Census data are 'unknown' in GlobalMapper - I will take a closer look at these tomorrow as this is the just released 2009 Census Tiger data.