I am toying a bit with the idea of Cordelia as a Slytherin-- I can never get over Ezar's line about "I've always felt that theists were more ruthless than atheists", it's one of my favorite quotes from Shards-- though I'm not sure ambition is what's required to command Betan intellectuals. Well, you need some to get the command in the first place, I guess, as demonstrated by her ex-fiance, but even so. On the other hand, she's definitely a capable manipulator once on Barrayar.