Gold drop isn't capped at floor 100. I tried it and I only got 1 million and something gold on the floor. I tried floor 150 and I only gained a little more. Floor 200 however, I gained 2.5 million from just gold drops. (This excludes dealer perk and I tested on packsize with magic enemies as I always farm on those maps and RNG gives me them like so easily now).
Floor 200 must be the cap for gold drops and item drops to be most effective as well because after floor 200, gold suddenly starts dropping to 1 million per floor instead of 2.5 million or so and items drop a lot less as apparently there's a bug that item drops doesn't work as effectively above floor 200.
Still, at floor 600 or above or any high floor for that matter and even floor 400, I got plenty of rare legends collected you wouldn't believe it. I mean 6 ragnarok chakram, a defiant gauntlet or two, 4 ragnarok hammers, 2 vaccus Scipio bows, 3 defiant pistols and skulls, 1 defiant trap, some malestrom gear with ease. Of course I also collected a good amount of epiphany rings too and cerebral Vortex, mashocists items, mayhem crystal (entropic jewel) , seven deadly sins, eternalized and so quite well. I didn't even try half the time (sometimes I did if I was in a farming mood).