This would do alright IMO.
I'm not rich enough to get it and happy with Animated Shockers, but it is freaking sweet.

As far as repaint/remolds go, a Darkmount remold with a gun that could cover/replace his robot-mode hand, or maybe SE Megatron, with a new head would make an OK Shockwave, since we're not likely to get a space-gun any more than we'll see a Soundwave as a tape player. I quite like Shockblast but he's no Shockwave ('cept in Japan).