In reply to llanberis36:
I think your one of your height and technicality criteria will have to flex- there are only 16 Andean peaks over 6500m:
http://www.andes.org.uk/andes-information-files/6000m-peaks.asp
and most of them are big volcanoes in the Puna de Atacama- remote and logistically challenging but technically easy.
Yerupaja is meant to be very hard. The Huascaran peaks are big and I think there are alternative routes to the standard one which might be suitable? Easy logistics too, as so close to Huaraz.
if you were to drop the altitude you’d consider by 500m, you’d have loads of options- Alpamayo suggested above is c5960m
worth trying to get a copy of this (even if you don’t actually go there- the photos are stunning!):
https://www.amazon.co.uk/Classic-Climbs-Cordillera-Blanca-Peru/dp/097586061...
edit- John Biggar’s guidebook is actually in print, and has a broader coverage- get both if you can!
http://www.andes.org.uk/andes-guidebooks-information.asp#The%20Andes%20-%20...
Post edited at 19:09