You sure about the P-38's having pressurization? Basically, I thought the only WW2 aircraft that had it were the occasional exotic fighter (Ta-152H), and some of the heavy aircraft (C-46, B-29...).
I don't remember seeing any pressure bulkheads in the museum's Lightning when we reinstalled the inboard fuel tanks (which are close enough to what would have to be the pressure vessel I doubt I'd have missed it). Also, I doubt the canopy (that rolled up and swung up) could handle very much diffy (differential pressure)...
Either way, I don't think AH should even consider modelling it for many, many moons. It's just not that big a deal, you basically set it at takeoff, then occasionally glance to check the cabin altitude, and the differential pressure. Let's put it this way, in my admittedly low, hours flying pressurized aircraft, you set the dial to maintain cabin altitude at, say 8,000 feet. And you're pretty much done. You might glance down at the gage, but it's just not a big deal... Now, as a creature comfort, it means the world, but I'm talking about the way it would apply to AH.
blk (AT)