Alright, I did this on my PS3 Copy of Oblivion before I got my PC copy, so I know this works, but the sheer ammount of time its takes is probably why no on efound out about it, but if you bask in the sunlight consumping copious ammounts of health potions (This is where the duplication glitch came in handy for me) you'll get a reduction on sunlight damage by 25% I think.

The wiki's don't mention this, so I guess it's that uncommon.

So yeah, give it a go and when you pull it off, post the message box that comes up.

And no, waiting will not make it go faster, I think it's set off via accumulated sun damage the player receives when a vampire.

Akin to the Magpyrs in Pratchett's Carpe Jugulum. Interesting.