Welcome to the forum, Mark!
Since you posted in the Casting section, are you looking for molds to cast the figures yourself, or are you looking for completed figures? Are you looking for contemporary USN, or historical?
Martiin Ritchie had color guards from all branches of our armed forces in his catalog, including both contemporary and historical. I don't know if he's still in business, though. He's retired from the show circuit for many years now. He was never online, either, but did business through mail order. If I can find his address, I'll post it back here. If you search the forum, though, you'll find other threads where Ritchie was mentioned.
Here is a link to a current auction for a pair of USN flagbearers:
http://www.ebay.com/itm/like/251523841549?lpid=82
If you are looking for molds, I don't know of anyone who makes molds to cast any American armed service, let alone the Navy. But Prins August makes toy soldier mold sets that produce figures that can be converted to depict most services, whether American or otherwise.
Hope that helps, prosit!
Brad