Rebirth (
www.therebirth.net) is definitely not dead. In fact, it's growing (I just checked and ~150 are online). Will they ever be the size of ScriptCraft? probably not. But the community is great because the players there are vested in their characters, since they have to level them from 1 like in classic WoW. I really like it. The devs are going fullforce, too. Movemaps were just implemented, so pathing is near-perfect for mobs and pets now (sample vid; turn down the sound lol:
http://www.youtube.com/watch?v=p7RSsFNuFis). Ony is fully scripted. Etc. Etc. And new improvements are coming out almost daily.
ScriptCraft is great and is excellent for those who want to power through to endgame. Rebirth is also excellent for those who want the full vanilla experience.