Personally, I am thinking of looking up the romance-able characters, and figure out if any vampires are available. If not, vampire bride here I come. Also tweaking any purchasable homes with some cattle, via either quest or purchase.
Add a chalice in game, that detects fresh nearby corpses. If activated it fills with blood. (Idea being it preserves blood for future cravings.) One charge, and adds in some annoying side effects. (Increased vulnerability to fire and magic, Temporary paralysis(like 5 seconds) - The unnatural preservatives don't sit well with you)
Add a ring in game - If your a vampire it negates sun damage. Downside is it also negates much of your vampire abilities. No vampire strength(or other skills), and no using of any vampire related abilities while wearing the ring. So in essence, your actually weaker then a non vampire while wearing it. (The other penalties still exist for being a vamp, like fire resist) -- Also the ring slows down blood cravings by 1/2
Create quests for the above items so its not so much of a cheat. (Although, with aforementioned negatives, I think it pretty much balances itself. Oh, and incase anyone didnt guess, I plan on becoming a vampire asap =)