Interesting concept, zerodish. I'd never seen this suggested before. If you don't mind, though, let me pulse you with a few questions and comments.
Before I lose 2/3 of the readers, I'll point out that the wheel deflects a bit on the bottom when ridden with a load. If it deflects enough, the spoke tension disappears (goes to zero), which is bad in two ways. First, it allows the spoke to unscrew, meaning the wheel goes out of true. Second, if the spoke doesn't unscrew, the spoke cycling between tight and loose will cause the metal of the spoke to fatigue, and ultimately break like a paper clip bent back and forth. It's actually better for the spoke to stay tight!
First, four cross is usually used for higher spoke count wheels, and two cross for lower spoke count wheels. The idea, as I understand it, is to get the spokes coming off the hub at roughly a right angle to the radius through the center of the hub. Are you advocating going to a 48 spoke wheel? If you're using 4x with 36 spoke wheels, are you coming off the hub at an acute angle?
Second, the ping you note as a new wheel is ridden is caused by windup of the spoke during tensioning and truing. This is normally fixed (by a skilled wheelbuilder) by over-correcting and then backing off during final truing. I don't see this as something that can be corrected by changing the length and angle of a spoke.
Third, the wheel is centered by balancing the tension of the right and left side spokes. If you're using the same number of spokes on each side, as is the case for every wheel I know of on the market now, you can lengthen or shorten the spokes on the left (non-drive) side, but the tension will have to stay the same unless you pull the rim off-center. With the same tension on the spokes, keeping the wheel centered, the only change is going to be frictional losses as the (almost) unloaded spoke shifts. This is unlikely to be significant, and so I doubt you'll change the load the wheel can take before a spoke goes to zero tension.
A better approach might be to replace box rims with a stiffer (V) rim. The V rim adds some structural rigidity, meaning you share the load across more spokes. This, in turn, means you can carry a larger load on the V wheel without the spoke losing tension.