Very cool work Silva. Tyson model is progressing nicely. I think it would be cool to see short hair/beard on finished model too, they're adding a lot to the character and accenting some of the forms (esp. eyebrows)
Travolta and Cage models look a bit rushed though and I think they're not on par with your other models
Btw, is mudbox is capable of doing production-quality texturing stuff? Or does one still need lots of photoshop?