Since you're using the US truck classification system, I'm assuming you're in the US.
If you don't live in California, you can buy the Freightliner Argosy as a glider kit, and put a pre-emissions engine in it.
Other than that, your only other option would be to import a foreign vehicle with Euro 6 emissions (which would be EPA2010 compliant). There was a fleet owner in Canada who imported some Scania cabovers some time ago and ran them for ERB, and some of the Euro COEs have been imported into Canada.