Yup. Turn the selector dial to the right (floor-defrost) rear blows hot. Turn it left (vent-A/C) rear blows cold. Using the fan I find this setup to regulate temperature well 99% of the time.
However, for that 1%.... Well that drove me nuts. That condition is when the seats are all full of passengers, and it's wet outside. I need the defrost to see out the windshield, but the back gets hot and stuffy fast with all 14 seats full (for one 3-hr trip, I had 28 people in the van when Next Adventure's Sprinter blew its transmission near Medford).
When my blend door actuator broke, I ended up retrofitting the blend door with a cable control. It was actually a universal Choke cable kit from NAPA. The knob is along the wall just behind the driver's seat, so I can reach back with my left hand to adjust it. Now, I can have rear A/C and front Defrost!
But, I still cannot blend the air. The blend door is before the evaporator and heater core, and the blend door points towards the air-flow. This means the air-flow shoves it tight in either direction. With my cable control, I can move it into the middle, but once I turn the fan one, it'll blow into one position or the other. To make the door adjustable, it would have to be flipped away from the air direction, and that's just not possible with the factory packaging, which is shaped the way it is so it won't intrude into seat space for row-5. Even with an electronic actuator, I'm pretty sure the blower moves enough CFM it would burn up the actuator unless the door were flipped.
I've though about this some, and I think the best way to have A/C and Heat at the same time is to install two separate fans for each duct, and use those to adjust temperature. But for now I'll stick with my binary cable control.
