Regulary flew 15 - 16,000 in South America.
Have done circuits at an airport with an elevation of 10,000 ft. Temp was 20C. density height was at circuit height DH was only about 250' short of service cieling at MTOW, which we were at. Bugger all wind so GS at approach and landing is noticeably higher due to high TAS. You keep Vref not one knot over. Brakes work hard but not as hard as the pucker factor on take off, even with a very long runway. (Quito, Ecuador)
Early days over there I was looking at a map and planning a flight from Arica in Chile to Cochabamba in Bolivia. A Wise older head suggested following the La Paz railway line to the border then cutting back SE across the altiplano to Cochabama, "Hey man, this is no biggie" I said, "we can direct track it pretty much, Grid LSA is like
63 - 68 so there is no problem, we just cruise 10k and we have room to spare!"
"That Meters, not feet, on these charts" 
Woops!
I removed my feet from mouth and tracked via the railway line at 15,000 visual between the magnificant snow capped peaks of the Andes.
Note to self, engage brain before putting mouth into fine pitch.
HD