I actually haven't completed it yet but I will post it online on my blog when I do.
My purpose in thinking of these new teams really is to breathe life and drama into the figures and the fanfic I am writing. These are the relationships I have deduced from the movie universe (movie, movie comic, prequel comic, Ghosts of Yesterday, toy profiles/tech specs, the video games):
Prime/Megatron: From what I have read, it seems Prime and Megatron are literal brothers, co-ruling Cybertron (like a di-archy) as dualistic aspects of a harmonious government. Optimus Prime served as fairness while Lord High Protector Megatron served as justice. But Megatron turned against Prime with an army of militaristic Decepticons, a new faction of seperatists, and the fact that their co-rule was so crucial to the survival of Cybertron, I think Prime despises Megatron for that. Megatron is happy to kill his ancient comrade turned enemy, but he also refers to him as 'brother' (see movie comic) several times, so at least he hasn't forgotten the old days. Drama has potential here.
Ironhide/Prime: Old friends, with Ironhide being slightly older than Prime (profile). Ironhide most likely is a bit more experienced than Prime, hence his cynicism, although Prime has a slightly more 'forbearing' attitude to the troubles of life.
Ironhide/Arcee: I see a lot of potential in this relationship with trainer Ironhide being a dark, brooding, cynical old robot and Arcee being the cheerful, enthusiastic hunter who tags turbofoxes in her spare time (profile). Also, in the Nintendo DS game it's revealed Ironhide was responsible for the destruction of some planetary body called Kaiba-5. I actually haven't played the game, but it's either a moon or planet. I'll let Ironhide struggle inwardly with his conscience, and the ramifications it has on those closest to him, especially Prime and Arcee. The dynamics potential is there for some good storytelling.
Ratchet/human children: Seriously. This could be really funny. Given that Ratchet's demeanour is that of a wizened healer, almost like those elderly elven doctors, he could be really fun to write about. I was thinking of a side-plot, where Ratchet and Bumblebee try to save an orphanage of genius children watched over by Sector 7.
Bumblebee/Jazz/Arcee: A fun loving trio, great to hang around with in peacetime, a deadly infantry tag team in battle. Nuff said.
Megatron/Starscream: Need I say more? Drama is what it's all about.
Blackout/Starscream: One is fiercely loyal to Megatron, the other, not. Ghosts of Yesterday highlighted this hateful relationship.
Prime/some human character: Unlike Bumblebee, Prime has no best friend who is human, and unlike Jazz, is slow to learn the culture. In many ways he is more withdrawn than the others due to his great burden. Maybe there is a human who can give Prime a respite from such loneliness.