I would like to have my heat pump controlled by the centrally located main thermostat during the day, but switch to a different thermostat located in my bedroom during the night. Is this possible and how would I go about wiring it? I was hoping it may be a readily available kit?

Another way to approach the problem is to use a T-stat with a remote sensor. Some stat's average the sensor temperatures. This one does not.

What you could do is mount two aux sensors with a toggle switch and LED. I think with a little logic and maybe a small relay, you can make the switch in either room similar to a 3-way light switch so that the bedroom switch and other switch can switch the locations. The LED on each sensor would indicate which sensor is used. The one in the BR can be very small.

For fun you can make a 7-day timer do the switching such that the programming occurs automatically. You would just need to keep the clocks in sync. The LED's would tell you which sensor was being used.

You could even mount 1 LED abouve the tstat and dispense with the other nonsense. Your timer could be at the furnace.

Swiching all the wires is not a simple solution because of the compressor protection built into the stat.

I think some communicating stats might allow control from two different locations, but it would not switch sensors automagicly.

So, I do think a 7-day timer with 2 remote sensors and one or two LED indicators.

Another way this might be accomplished is to install two programmable thermostats and wire them in parallel (both wire the same, to the same equipment) set the main thermostat to be unoccupied at night and the bed room thermostat to be unoccupied during the day and switch from occupied to unoccupied at the same time, when one goes to occupied the other goes to unoccupied. Good luck, Mike

There is a simple way to do it if you don't have or want to go with programmable thermostats. Just run a cable like the one to the existing thermostat from it to the new thermostat. Connect all the wires except the red together at the first thermostat and to the proper terminals at the new. Connect the red to the common of a SPDT switch. Connect the red of the new cable to one of the other terminals. Connect the third terminal to R or RH and RC of the original thermostat. Depending on the position of the switch, only one thermostat will have power at a time.

Labman: You might get poor backup battery life with your method with the new-fangled stats.
So, selection of the stats matter.

Add a zone control system. You have two thermostats, one for each level. Dampers will open or close for the area that is needing heat or cooling.

Well, that's another way of looking at the problem. I was looking at his problem as an energy saver. At night all he cares about is the temperature in his room and nowhere else.