Put the first 6 ingredients into the bread-machine, in the order given. Set on dough cycle. At the end of the dough cycle, take dough out of machine and let rest for 10 minutes. Roll dough into roughly a large rectangle.
Mix brown sugar, cinnamon and butter together to form a paste. Spread paste on dough, leaving 1/8 away from sides of dough.
Sprinkle with nuts, if wanted. Push nuts slightly into dough. Roll dough into a jelly-roll shape. Dough should be very thin. Then prepare the sticky filling. Boil the brown sugar, butter and corn syrup. Separate the filling evenly between 12 muffin cups, then slice the cinnamon rolls, and place one in each tin, face down. Let the cinnamon buns sit and rise for 35-40 minutes, in a warm place.
For the frosting, cream the cream cheese, and butter together until light and fluffy, with no lumps. Add sugar, then the vanilla. If mixture gets too stiff, add sufficient sour cream, a tbsp at a time till the right consistency, Not too thick and not too runny.