I would shoot for less then 3 lbs myself but it "probably" could lift maybe 5 or 6 ??? Type of blades, pitch, and thottle setting will vary the amount. I put 5 lbs on my Raptor 60 and it was like flying a dump truck. Of course 8 lbs on my gasser was "noticable".

Getting a light small camera would be the best bet. Something like this is perfect. I am no fan of wireless but have seen some good ones.

Heck... I have seen a mini DV camcorders zip-tied to a 50 with good results!!!

Edit:
Here is is http://www.rcuniverse.com/forum/fb.asp?m=3623970