I am concerned about the Ardino dying
I understand all of that, my Arduinos have worked at Shuttle launches 2010-11. I had no problems, they were in Pelican cases and well protected. Even with all the forces, the Arduinos were 400 ft from the launch pad, the Duemilanove's worked great. I just looked and I can't get Duemilanove's anymore. No stock. So I will have to go to Uno R3's unless there is something more reliable.
The Minis can be not so great long term from what I hear.
If you are having problems with rough environments, maybe you should just try and "pot the whole board"( minus the connectors you will use)... paint it with epoxy resin. That should seal it and still allow for heat transfer, if that is any kind of issue.