Items similar to a collar of umbral metamorphosis?

[gallagher]

so by spending a mere 22000 gp, i can get the dark template for free. i have a high level character who has no issue of money (Persisting cleric)

are there any other items that grant me a template?

[Thurbane]

CoUM is the only template granting item that I am aware of...though I'm fairly ignorant of setting specific (FR/Eberron) splat, so there may be some there.

Not a template, but the Heart Talisman of the Red Dragon (EtCR) effectively gives the Fire subtype 1/day.

[Signmaker]

Ghostwalk (3.0) has a few, though if I recall correctly you usually wind up dying in the process. Still, a remarkably easy way to go vamp.

[Andion Isurand]

http://www.wizards.com/default.asp?x=dnd/fw/20030323a

Ring of the White Wyrm