The inhabitants of the planet Ultron could have been seeded by the Preservers with genetic stock from the planet Gallifrey. Like the Time Lords, they have unique powers, but physically they also have two hearts.
The Ultrons also have six toes on each foot and their knees are double-jointed. We don't know if the Time Lords are as well, but I don't think we've ever seen the feet of the Doctor closely, have we? (Maybe in "The Two Doctors" when the Sixth Doctor went fishing?)
And who knows if they're double-jointed at the knees?
Supposedly Ultrons have an extra male sex organ, something Jackie Tyler was quite curious about when she inquired after the state of the Doctor. And both races can regenerate, although I don't think it was actually mentioned as having happened to George Sunday aka Thermoman (although we did see the results once the role was recast).