Vampire template has always been on my wish list as well. Actually, I can remember people asking for that early, early in the PRC's evolution. Now the template system is really up and running, perhaps it wouldn't be as hard as before. A lot of the basic undead features are already well implemented in necropolitan, lich, and demilich. All that would be needed would be for someone to take the basic undead features and add the vampire specifics--granted, some of those might be taxing. Still, at least some of the groundwork has been laid.
By the way, I played the demilich not so long ago (with a cleric/dread necro/true necro combination, so I got lich automatically and just needed to add demilich). Now there is a great template implementation! True, the template is different from that implemented for the lich/demilich class, so the damage reduction isn't quite as absolute, but that probably makes a better balance for game play (so a really powerful opponent can damange a demilich physically). Various spell-casting enhancements and a real fear aura certainly help. For high level games one can create a very powerful but also very flavorful undead character. As always, the PRC team has done a great job.