Sayako. Lol idk. I just think that Lulu x Sayako is more interesting. No one really knows that much about Sayako, so in a doujin, the author would be able to twist her personality to anything he/she wants it to be. It's really hard for me to imagine Lelouch in a romantic relationship with Kallen or C.C., 'cos it just seems to me like he'd never be interested in them in that way. I'd totally buy a Lelouch x Nunally doujin though. Incest pairings are really creepy, and they always disturb me until I actually read a doujin or something of the pairing.