nailboards in hardware

quick & simple: does today’s graphics hardware support nailboarding yet? if no, is there any good alternative out there?

thx
hoshi55

You mean as described in the following paper?
http://graphics.csail.mit.edu/~gs/papers/12_nail_97.pdf

If so, then yes, modern video cards can adjust depth values on a per pixel level. Any video card that supports ARB_fragment_program should be able to do it.