You can use stairs with a dumbell to do one-legged calf raises below parallel. I have to admit I don't know how going below parallel will change the look of the calf muscle.
Going below parallel is just taking the muscle (calf in this case) through it's full range of motion, but make sure that the motion is slow and strict with a hard contraction at the top. If I were you Beef I would do standing calf raises with a bar on my shoulders and just use the floor, and then do raises on the stairs to get that extra stretch.
In QODs opinion to develope great calves it's all about keeping the muscle contracted for as long as possible, and if one looks at women who wear heals all the time you'll see that for the most part they have very solid calves.