Wow,
You guys have been busy.
My take on it...After I created my sabre way back when out of a King Sol, I came to the conclusion that it wasn't a king sol that was used, thus one of the reasons I sold it.
At the time I didn't know there were so many others who felt the way I did so I kept quite about it.
To me, it does look like a MPP but the area of the wires is what always confused me.
Could possibly be wires, but they'd have to be some thick wires I'd say. The CF pictures are pretty dark and I would't think a dark wire would show up so clearly in the pictures.
In regards to the wires in the ANH sabre, yes there are wires running out of the bottom of the Skywalker sabre in Ben's house. That wire as EDC pointed out ran the motor inside the tube and ran down Luke's arm to a pack attached to his back.
I've never seen the wires in the scene when Luke get's his hand cut off but I'll look. THere is a good shot of it in hte MOM companion book. It was there that I first thought that the sabre could have been used for Vader's ROTJ sabre.
Another thing to consider is, isn't a King Sol shorter then an MPP? And if the shroud was sitting on the King Sol, doesn't it sit lower then the shroud on an MPP?
So, why doesn't someone do a comparison of where the sabre in the CF chamber shot is sitting (endcap end) in comparison to the first scene in ANH when Vader enters the Tanative IV and see if the sabres are resting in the same place or if one is sitting lower then the other?
My initial take on the last photo link posted is that it's an MPP and the grips aren't longer but the clamp is lower down on the tube. But that could be an optical illusion also.