hey Valencia1. I don't know about LEATHER pants, but i got textiles that fit my fat a$$.
I'm 5'11", 285lbs and I wear a 44-46 in pants. I got these Fieldsheer Mercury 2.0
size 4xl. They have a lot of room to spare for me.
If you're looking specifically for leather, I'd try stopping by some shops/dealers to see what they have to offer.
Also, if you're out in Valencia a lot, you could meet up with me to try mine on if you want to. I live/work in Valencia, so I'm always out here. PM me if you want.