Mine hasn't broken yet, but I think I'm one of the lucky ones and I've not messed with him too much. The Takara version doesn't suffer from the plastic quality issues that the US Hasbro version does. The color of the plastic is darker too, closer to black than brown which is more show-accurate.
Sadly, I checked ebay and every online retailer I'm aware of (which is quite a few) and couldn't track one down for you

. My advice would be to watch ebay for it.
The one you're looking for is listed on
this page under
Variations as:
Metals
Megatron:
(1999, Japan)You'll notice the slightly different colors to the plastics he's made of, including the beige/brownish panels which have a more pink/redish hue and the plastic his arms, legs and torso are made of, which is more black than brown (brown being the problematic plastic used in the Hasbro/US version).