The 85mm F/1.2 is a beast and rated as one of the best Portrait lenses that Canon has to offer. It's also a very expensive lens that's not super versatile. You can't shoot macro, in fact the minimum focal distance is a few miles away (i'm joking). So unless Portraits are all you ever do in life, most people won't invest into that type of gear.
I've been following a company called Borrow Lenses for quite some time but never had the nerve to test out the service. Basically you place an order on line and they ship you the gear. Don't let the name fool you. It's not all Lenses. They've got RedRock Micro shoulder rigs, follow focus systems, full camera bodies, light meters, tripods, filters, Memory Cards, Lighting. Brands include Canon, Sony, Nikon, and more. The above video was shot by someone in New York! These guys get around in renting professional equipment for both Photography and Video.
I've had the chance to work with many professionals in the field lately and they all seem to be doing business with Borrow Lenses with absolutely no problems. Located in San Mateo you can even drop by their office for pickup and drop off. They even have a YELP review page. So the next time i'm thinking of dropping 2K on a lens, maybe i'll think about just renting it for about $34 dollars for a weekend. Click here to check out Borrow Lenses.