Well, this forum looked lonely, so I decided to go for as high a score as I could without dying. I ended up making a dumb mistake and dying in Marble Zone Act 3, so my score is pretty pathetic: 164,130. I hope somebody will try to beat that.
In case you haven't picked up on it, by the way, the no-death rule is the only way to have a real high score, as your score can stack with extra attempts.