This is a nice one on several levels though maybe not obvious at first glance.
Checking Google -> 75,000,000 results for "certified" sure seems like a great base to work from ... 19,500,000 results for "certified" "us" not too shabby either.
The thing that caught my eye right away was the "domain hack" vibe - I wasn't really sure what to make of that though. (I love domain hacks but not sure if they have much intrinsic market value in general - seems likely that there could even an "anti-premium" for too much cleverness for the general public.)
Still "certified.us" seems to stay on the sane side of hackiness if used in that way (ie with subdomains either along the lines of "grade-a.certified.us" or even something like "ms.certified.us") - it keeps the keyword intact and adds two possible interpretations of the ".us" extension - "US" as in country code + "us" as in "we".
All that being said, the $$$ value seems likely to be in price range I have no experience with so will have to leave that estimate to more high-end resellers. If had to make an uneducated guess, then might venture to say at least $xxx reseller and probably $xxxx or more for the right end user.
