" build a lightweight box around the tank, leave 4 to 6 inches around the tank. use the great stuff spray foam to fill the box"
Yes, I'd thought of this approach, but spray (expanding) foam would make it difficult to perform maintenance.
Like the Water heater insulation jacket, I was hoping to find a "pressure take insulation" cover of some sort.
The enclosure idea might work with regular (removable) FB Insulation material.
One of the issues is that the tank is integral to my water system and removing it for a day or two to "fix" it is not the first choice. Better to have an ideal solution ready to go before having to disconnect one's water pipes. And, any such solution must provide for re-connecting the 1" pipes after the "solution" is in place.
The way the Pressure Tank is installed, I was hoping to find a "clam shell" affair that could be easily attached and removed if necessary.
The drip pan and pump system would work, but it's too Rube Goldberg for my tastes.