I do giant sets with a few of my clients. I use them more like mini-circuit training than a "blast the hell outta one muscle group" crazy shit.
I had one of my more advanced trainee's doing the following this morning:
Front Squat/Overhead press combo X8 straight to
Pullups X8 straight to
Rear-delt Flyes X8
(Yeah, I know, technically this is a Tri-set)
Rest 60 sec & repeat.
Yup, he really wanted to puke and get it over with by the time we got to the next sequence...