Aside from some dorky modeling shots, this is about as legit as it comes. These amazingly faithful recreations of the weapons of the 'Earth's Mightiest Heroes' were done by BuriedByBricks. I don't recommend hitting anyone or anything with Thor's hammer though. As much as I'd like think it would just break into a thousand pieces and be funny, it looks pretty solid and would probably do some serious damage.
The only Avengers left out of the LEGO arsenal are of course The Hulk and Iron Man. It'd be pretty hard to recreate Hulk's 'rage' out of LEGO pieces. The best representation may be just a wreckage of LEGO pieces scattered throughout the room. As for Tony Stark... maybe some sunglasses and a martini glass? That, or get crackin on that whole suit!
If these were put into production I'd definitely have to pick up a couple of them. Check out the digs, and let us know what other props from The Avengers would be cool to see in LEGO form. Nick Fury's eyepatch perhaps?