I loved using Giant sets, when I was at a gym that I could do them at. My current gym just has far too many people, and it's hard enough to do straight sets at times!
Candidizzle- here is a Giant set that I would do for quads, for hams you'll have to use your own imagination (and we all know you have quite an imagination!):
Rev. Hack Squats (525 Tempo)
Leg Extensions
Hack Squats (normal stance/cadence can be 22X)
Smith Machine "On Toes" Squats...instead of being on a block of wood, just stand on your toes as if there were a block under your heels and hold that way
BB Lunges
45* Leg Press
No rest, just keep going. The first set you might think "This is easy." Then after your 60-90 seconds of rest, you'll be nailed to the wall- HARD. Make sure you feel the muscle doing the work, DO NOT let momentum take over.
If you usually do 225 for Hack Squats, I would use around 185 for them here, possibly less. Depends on the person, the fortitude they have, and how much they're willing to push.