Theirs about 15 well done use made missions released for Operation Flashpoint Dragon Rising so far... most are listed (linked) in the mission depot thread, in the OFP DR forum.
Most came from either the official Codemaster forum, or the new fan web site OFPDRHQ.com.
The missions range from defending a town from a major assault, including gunships overhead, the enemy using smoke to conceal the assault, and other well done features, to Cobra strike missions on a convoy and a SAM site, and assaults on a compound with air support, and ending with a defend the castle for a set amount of time from the waves of enemy forces... real intense.
Most of these missions can be played either by yourself, with AI... or in co-op mode. Be sure to check them out and post a note of thanks when you like one.
BTW: I did not make ANY of these missions myself, just to be clear.)

Yep, thats their bodies falling out:


The enemy drops a wall of smoke to conceal the assault:




Hey soldier, you might want to use that concrete house for cover instead of that wooden dog house... just a suggestion:







I really wanted to play "Ride of the Valkyries" here:










Defend the castle till extraction:





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