Thanks for the information. **EDIT***
I found the flow path information here:
http://auto.howstuffworks.com/cooling-system2.htm
So it seems that a non-opening thermostat WOULD cause back pressure through the system, which would blow out the only available hole/path- through the bottom radiator hose, then up and out through the cap... correct? This would explain why it does not start tossing water until after it has run for 5-10 minutes... Also, if the thermostat is blocking all hot water, then it never has a chance to enter the heater core (as heated water)- so the water pump IS only pumping cold water into the heater core....
Maybe? lol