Okay, I found the twins in DOTM.

The scene where the Xanthium takes off with the exiled Autobots - we see a Decepticon jet shoot down the Xanthium. I've always assumed it was Starscream... TFwiki says it's Starscream. But 5FDP pointed out to me that this robot mode has blue bits on him! Does that make him Thundercracker?? Aside from the blue, we only see this Transformers speak in Cybertronian, thus we never hear Starscream's voice (granted he only sounds like that when he speaks English -- his Cybertronian voice sounds generic). But then... he has alien tatts like Starscream. And later in the film when we see Starscream, he doesn't have any blue bits on his robot form.

So... does this mean that the Decepticon who shot down the Xanthium was Thundercracker (or maybe some other blue Decepticon... Dirge?), or was it Starscream who decided to go Smurfy when he shot down the Xanthium... maybe "Deep Space Starscream"? (sure beats Hasbro's Baby Blue) The jet mode looks completely like Starscream... the blue is only visible on his cheeks and I think a few other parts of the body - but it's subtle. The rest of the robot is still principally gray like Starscream. But Starscream is completely devoid of these blue highlights later in the film.

Here's some pics for comparison:
http://tfwiki.net/w2/images2/b/b1/Starscreaminorbit.jpg <--BLUE CHEEKS!
http://tfwiki.net/w2/images2/a/a8/DO...rscreamSaw.jpg <--no blue!

Maybe Evil Betty from Kung Pow's up to his old tricks again and changing Starscream's colours... "Your face is blue!"