Surprise, surprise
Of course now I find out that indeed even my relatively simple prototype for the Scooby week view leaks memory like a sieve in IE. Yeah, it had that allocated memory in a seriously vice-like deathgrip. Ah, such a joy.
After tracking down the offending closure (an event handler, natch), everything's solid again -- and you can bet I'll be a lot more careful even when I'm in 'blow and go' mode, roughing out a prototype like this.