So, in my campaign I would like to offer the PCs immortality in undead form / have them be turned undead but have found nothing that really involves this idea in 4th edition. I bought Open Grave hoping for something like it, but all I found was undead grafts - intended for NPCs!! Dragon magazine has the Revenant race and Dampyr bloodline but neither of those is quite what I want.

My idea is to combine the Dampyr bloodline idea with an undead graft a piece to create a sort of template to put on the PCs. When they turn / are turned undead they will get a free feat called Undeath which will make them undead for game purposes, unlock future feats if they're interested in reveling in undeath, and whatnot. Things like Dampyr's +1 speed feat. Depending on the player, they might get a graft like the zombie arm so they can have a natural attack. Maybe. Not so sure it would ever get used though >.<

The way the game is set up I don't mind if the PCs become evil or become good (they are mostly Unaligned now) but I want the temptation there for "Oh, hey it is actually sort of useful to be undead."

Has anyone tried this or done it successfully before? Any tips? I will post more specifics when I work them out a bit more.

The PCs are : a Tiefling Bard (the party leader) a Human Rogue (the impulsive one) a Human Fighter (the 'let's beat our way through this' one) and an Elf Druid (the conscience of the party).

The game world is low wealth: the PCs are level 3-4 with 2 magic items each and about 100gp each.