This has been going around for the past day or so. Michael Yon (currently swamped) has a photo of a bizzare contraption that looks suspiciously like a Redneck RPG:
This could be some sort of toy or trainer. It could even be a home-built functioning rocket launcher of some sort.
Murdoc, however, suspects that it could very easily be nothing more than a prop built for use when the media stops by for a photo shoot or for making jihadi recruiting videos. I’ve not noticed anything like this in Reuters and such, and it seems that there’d be plenty of real RPGs laying around to use for filming (and training, for that matter). But unless we get some more pics I’ll stick with my guess.