I've seen a couple of aftermarket cross-members for 2WD trucks, and they are usually used to give more space for dual exhaust. I think a vendor on Summit offers one, and there is a place in Texas that builds them. However, I've not found one for a 4WD truck.
There was also a factory dual exhaust option in the 70's, which may have had a W-shaped crossmember with more space, but I've never seen one to check it out. With a stock crossmember and NP203 my '75 has plenty of space on one side for the exhaust, but barely enough space to fit a 2" exhaust pipe on the other side. I have to keep the exhaust hangars really tight so the pipe doesn't bounce up against the crossmember when going over bumps.
Bruce