I think the report you are making him do is a super idea. Stick to it Dont give in.
IF he doesnt do it them take his most prized priveledge away for "X" amount if time.
I know you said taking priveledges away hasnt work but you need to keep doing it regardless.
He's starting to test you now so its more important then ever to stick to your house rules and morals.
Find out if he made a new buddy at school / Facebook (?) . Something or someone may be influencing him to be a badass wanna-be ..
Good Luck, let us know how it goes with the report...