Regarding the knee articulation issue: I've seen two pictures of Structor/Scrapper that could provide evidence for such articulation. A Google image search for "TFC Toys Structor" turns up an image of a mostly green prototype connected to a Heavylabor, showing what appears to be a slight knee bend. I've also seen a grey prototype rear shot of the vehicle mode where the connector port looks to be designed similar to Munitioner's. If a rear shot of the combined form ever shows up, that'll probably go far in dispelling the mystery.
I'm hoping he does have knee articulation. I can easily believe that Hercules won't be very stable in bent-knee poses, but I'd still like the articulation to exist.
EDIT: Also, close-up shots of Mad Blender's head appear to show a hinged combiner port behind it.
Oh, and on another topic, I'll put a rough estimate at the combined figure's height at 15 in. based on the vehicle mode Exgraver in front of Hercules. I was actually hoping it'd be a bit shorter, like 12-13in., but I still like the look of this one over the Maketoys version.