/ Certificate of Good Conduct (no criminal record) from the USA
I'm living in Poland right now this is why it's more complicated...
Cant you send a power of attorney duly notarised by the embassy to someone who can get it from the local police station on your behalf(if you have a valid driving license as I gave it to my wife who picked it up for me and mailed me)This was all over 10 years back though.In any case you can call your local police station and ask.You can also call the embassy citizen services consular and ask for solution as well.
I would recommend starting with the FBI.
That is a long process(around 4 weeks) with fingerprinting etc and the fee I remember was around 50$,I know thats what one has to go through for state lottery,liq license and firearm licenses.Again that is a criminal background check and not a character of good standing certificate.