Sean, that's easy to achieve. No controlled room -- just an airconditioner at constant temp blowing on the amps 24/7. And another room for the amps. And someone to foot the electricity bill, of course... :)
Weather-induced amp performance variation
There is an excellent article on HiFi News current issue about how temperature affect an amp performance. It actually measures how the bias changes with different room temperature.
It may have something to do with people who notices there is a change in their hifi system in different weather.
It may have something to do with people who notices there is a change in their hifi system in different weather.