I saw one done like this recently, had to take my turn at it. I got Laser Op (cab only) off ebay recently, but he was really loose and didn't come with his ab-grill. I found a PERFECT fit using the chest piece from Classics Megatron. I made the laser blaster out of a kryptonite missile launcher from a Superman Returns Lex Luthor figure. Just needed to grind off the Kryptonite. Now that's irony.
I just recently did one of these, I love the mold but hate the colors it comes in. I also just got him a replacement sword from Darkov. Now I kinda want to find his trailer and paint it up in a G1 style. Later
Again, I like this, but I think finding a ready-made part could improve the look of his abdominal plate. It's really cool that the Megatron chest hatch fits there... but maybe if you found a cheap toy truck, you could remove the front grill and simply super-glue it onto the Megatron plate you have right now... easy detailing! zmog