I seem to recall them going on sale in late May in 2009, I would guess they have a twice yearly sale.
An AB800 through a 64" PLM would be a bit of overkill in the space you've described, for what you want to generally want to shoot. For children and babies, you want a softer light, generally a more narrow depth of focus, which will be hard to get with a 320 w/s B800 and a PLM. If you really want a bee, B400 is the way to go. I agree with the poster about a smaller speedlight, should be plenty, and a lot easier to place in a small room than a monolight. 