I'm 6'8" (yes really), and I find it hard for trousers and tops.
I use the Viper UBAC in Large, the cuffs are short on purpose for all, but for me it looks funky (meant to roll 2+ times anyway).
I also use the last gen British military UBAC in the largest they had without being fat (new one has shortened cuffs, this one did not).
My legs I have the British military genuine MTP trousers with 34" inner leg (larger crotch area means it fits my 38" inner leg)
I also wear the Viper Crye clone trousers in 38" waist, turned out the bottoms an inch or two and they don't look too bad with boots
Good luck my lanky friend