Was this the kind of thing you were visualizing:http://tfwiki.net/wiki/Star_Wars_Transformers
I think it's complicated to negotiate a deal like this, as you not only need the permission of the franchise you are making into Transformers, but also the permission of Hasbro to market them as Transformers and make the toys.
For example, the Frozen franchise holders might not agree to using Elsa in this way because they regard it as unauthentic (there are no giant mechanoids in Arendelle).
What do you mean by Marvel Transformers?
Please clarify that statement.
Do you mean the Generation 1 Transformers?
That is the term used to define the original first cartoon series and it's characters.
But now I am wondering, if Disney acquires the rights to Transformers, will they make their own animated series?
And who would they use as the basis of the series?
Most likely, I'd expect to see the live action Transformers, as that's the most recent iteration.
But that would be incredibly complicated to make playable figures, as they have insane amounts of kibble (that's a fan term meaning unnecessary visual clutter).
I do remember the toys were less kibbley, as they had to be realistic:http://i637.photobucket.com/albums/uu100/zrowngctr/Transformers/BarricadeampBlackout_zpsd9a4d5cd.png
So maybe these would be easier to make into figures.
But they'd need to secure the legal rights from the movie studio as well.
I know that there's currently some kind of legal dogmangering going on with 20th Century Fox refusing to surrender the rights for certain movies which stops Marvel from actually using the concepts from those movies in their official licensed online game.
My head hurts now, too much thinking about legalese!