Since it looks like the time window for Takara's Lamborghini license has passed they cannot release a Sunstreaker. They would have to reapply and pay fees, possible profits on the figure. Odds are if they were going to release it, it would have been released already. Why pay licensing fees twice. It makes no sense.
Its also possible, that Lamborghini did not approve the car designs for Sunstreaker. Sunstreaker transforms into a “modified” Lamborghini Countach LP500S. Possibly, they didn't want a design that technically isn't a fully Lamborghini design. I have heard Lamborghini is funny that way these days.
The truth is no one knows for sure, but I certainly wouldn't expect Sunstreaker from Takara at this point. Because it ain't looking good. Which is why I just pre-order this guy.
Fun Fact: Sunstreaker was designed by Koujin Ohno (Takara Toys) and is credited as the first "Car to Robot Transforming Toy" ever made. It appeared first in Takara's Car Robot Series in 1982 before being used in the initial wave of Hasbro Transformers in 1984.