Height isn't always relevant to inseam, though--I mean, generally speaking it's loosely correlated, but I know girls who are 5'4 and have 33" flats inseams because they're all legs. But yes, generally, denim buyers tend to consider 34+ to be a "long" inseam.
Though I don't come from the perspective of a leggy girl (far from it), as a seller who's measured probably thousands of pairs, I notice trends every once in awhile. Obviously R&Rs are all quite long, but since they've pretty much bit the big one, they're not as readily available. Also, of all things, a lot of straight-to-discount 7FAMs have 35 inseams, as well as many J Brand styles (not necessarily the skinnies though). And these are not necessarily a denim brand, but the Alice + Olivia pants I've gotten to measure (both my own and for resale) have had ridiculous inseams, usually over 35.