MP-10 is almost a head taller. There's a comparison pic I included a page or 2 back. Inevitably, either iGear or Takara will redo MP Megs smaller, and I'm guessing it'll be iGear first, if at all. The pic of him smaller just looks better proportionally, especially with the sized-down cannon. Of all the complaints I had for MP-05, it was that his cannon was ridiculously too big in bot mode.
If Hasbro/Takara redo him, it'd be awesome if the scope actually collapsed into a smaller cannon. Doubt that'll happen, but who knows.
As for the Bumblebee, that 3D model looks amazing. Takara should just buy iGear and let them do business for them. Heh. I don't know his scale, but hopefully he won't be too close to scale in vehicle form to Ironhide, or the bot mode could be too small.
If he's 1:32 though, he'll be roughly the size of Alternity BB, which means he'll be at a decent scale to those guys. There's also a Cliffjumper they teased, but only a leg shot. Looks like he'll be more than a red repaint with a new head. Looks to be an entire Porsche re-shell!