I do remember reading something out of Toyota Japan saying that IF they brought the Supra back it would have an N/A v8 based on the Tundra v8...but bored/stroked out. And it would be as a "race car".
I think that now everybody is missing the Supra that if they could bring it back even with a v8 that it would do well as long as they kept the price down to compete with other sports cars. The reason the Supra, and all those high-end import sports cars got axed in the late 90s, was because of diminishing sales abroad. The market was too full with them, but I think '05 would be a great year to release a Sports car...there are very few "true sports cars" left.
I don't see it being a hybrid. I highly doubt Mitsu will go through with their Hybrid Eclipse concept either. People who buy sports cars aren't as concerned with gas milage and pollution as those SUV-haters are. I bet most people who own a sports car as a "weekender" also owns a big v8 suv that gets 11mpg :-D