Play set folders too small
I haven't seen anything bigger than 480, unfortunately, that wasn't a binder.  Quadrow Collector Albums like this one are probably your only real shot at more than 480, and of course they're binders.  They can hold 30 pages of quad row, double-sleeved cards (so, 24*30=720 cards), or 36 (single sleeved) or 48 (not sleeved).  Quite a lot.
There are some 3x3 page ones that are bigger from smaller companies, but I have to imagine the quad-row is a big benefit to your particular storage needs.  I guess a 9-card page could hold 2 cards (x4) plus one blank space in the middle or something, and still hold all in one binder (like this one); that's 720 cards, so if you only used 8 per page you'd get 640 out of it - but not as neat looking as a quad row for sure.
I think the issue is that the thickness of a 480 is about the maximum thickness people are comfortable with - plus probably some construction issues.  That 720 one looks really, really thick to me, uncomfortably so, and I'd worry it may bend the cards more than a smaller one would.