Why not just use a regular green laser and use a small heating element to keep it warm? In fact, even insulating the laser might allow it to keep warm under it's own heat.
My first choice is ready to go, but if there is a ready to go "heater module", i may try to use it. But i do not want to mess with the laser. Plus heater will need controls maybe some sort of thermostat to make it on at low temperatures and make it off at normal and elevated temperatures.
Do you know any ready2go heater modules for lasers?
By the way DJNY i've checked your suggestion but i was unable to get a datasheet, it just says extreme temperature repeteadly, and i do not think it is reliable.
The diode will heat up from inside. If the diode is powerful enough it could warm the crystal in order to get a decent green output.
You need to keep the laser in your warm pocket anyway and take out when you use it. The batteries don't like minus 30 Celsius too.
Why not just get a cheap laser and wrap it in some insulation? I bet after a few minutes of warming up the pump diode will generate enough heat to get it back to operating temperatures. Of course then you need to be careful you don't overheat the laser.