I seem to recall seeing a mod that added MANY lore based races for the player to play. But as TESNexus has almost one hundred pages of race mods and you can only view ten at a time I thought it faster to ask here.

Also, if you play a vampire race what happens if you cure yourself of vamperism?

-Ryan Paul Fialcowitz

I think you might be refering to COBL-races, or maybe Race Balancing Project. Each add a bunch of new lore-friendly races.

there's also http://tesnexus.com/downloads/file.php?id=28814 at tesnexus

Note that they're both pretty much the same thing, except COBL races is outdated and missing one of the races that RBP has. I think COBL races might also have the option of avoiding gameplay changes/balancing.