Martyr

wut about a martyr. It would take damage in order to restore the health of an ally, and if you sacrifice all your health, you can revive an ally.

It sounds more like you are sugesting a skill or 2, not really a idea for a class.

Though I think Nebojats his Revenant does such a thing.
If you'd like you could offer your support and demand Anet makes the class.

Infuse Health?
Flesh of my Flesh?

These skills are basically your entire post.