IF2 you are misinformed. For RVSM purposes only, the definition of "state aircraft" is MILITARY, POLICE, and CUSTOMS. This seems pretty definitive.
Secondly, you taxpayers would have to pay for RVSM compliance. For a C-21, that runs about $450,000 U.S. per airframe. You are very generous with your fellow taxpayers dosh methinks.
I hope this clarifies your concerns, sir.