From what I have seen, 37 inch tires on D44's are fine. The only real issues are driveability, which is managebale with a light right foot, and drive shaft angle, which I will have to adress almost immediately. As for the chromoly axle shafts, you are right, this would be a good idea, especially for insurance but we will see what happens.
Why so against the 37 inch tires? I agree when you say just becasue you can, doesn't mean you should, but it has been done time and time again with little to no issues. If something breaks, hopefully it won't, but if it does, it does. By the way stock tires are 32" and 35" can fit with zero mods, but will rub off road. Therefore, I thought 37's was the way to go. Maybe I am wrong, but as always, I am no pro and am all ears.