Saudi Arabia fits perfectly into this scheme as well as Russia, to a certain extent
I hope this argument never catches on, government is not a productive enterprise. Its main function is to oversee, also I think you've not considered all the debt of public bodies. If you include the entire nations GDP then you have to include all the debt as well
Indeed, government is not a productive enterprise. Just like the board of directors of a company ain't either. It is the nation which is an enterprise that produces goods and services. And the government is, as you might have already guessed, its board of directors. Regarding the size of the US national debt (which was used in my analogy), you can take it from here. I can't say how authentic their figures are, but they should account for the total national debt, including the debt held by the public and the debt held by government accounts as well as intragovernmental debt...
As I understand it, the latter two should be excluded from consideration
Debt clock is pretty good for ballparking, especially if you're looking for an overall debt level in the economy. But including state and local debt in the national debt numbers isn't realistic, since state-level debt doesn't get tacked on the national debt. There's no precedent for doing so, at least. For exact numbers, I like the Treasury's website. They publish the federal debt (to the penny!) every day that takes in to account all the notes the federal government issues to fund itself. It includes public and intragovernmental holdings: http://www.treasurydirect.gov/NP/debt/current