You could try jumping squats. That's the only way I know how to describe it. I think its amazing for explosive speed and jumping. Last year around the Super Bowl I saw a training session with Troy Polamalu. I absolutely despise the Steelers (I live in Baltimore), but I will give props where they are due and Troy is an exceptional athlete. Not good, not great, he's exceptional (I won't get into a big Ed Reed vs. Polamalu debate). The guy is quick, explosive, amazing athletics.
Anyway his trainer had him doing what looked like jumping squats to aid in his leg explosiveness. The way I saw Troy do them was on what looked like a standing calf raise machine (don't know if it was modified or not), you could also do this on the smith machine. It wasn't a lot of weight, but he would get low, thighs about parallel with the floor, and then push up and at the top of the squat movement, jump off the ground. It wasn't a "jump as high as you can" type jump; his feet came maybe 6-8 inches off the ground (guesstimating)
Anyway seems like it would be good for vert and overall leg explosiveness.
I'm at work so I can't search youtube for a vid of troy training, but I'm sure its probably on there.