No, druids don't have a "restealth" ability in cat form.
Thanks to one of my favorite changes in some recent patch, us night elves (of any class) can use our racial 'shadowmeld' to drop combat and disappear, but then we're stuck in one place in caster form. It's fabulously useful in getting out of PvE fights that you don't want to be in, and for dropping or transferring aggro when you're DPSing an instance, but in PvP players know right where you're at so it's value is minimal.
Edited, Nov 28th 2008 8:30am by JeeBar