Well, I just ordered one of their enclosures, the 4-bay, 2-board (master/slave x2 one) with removeable (though not hot-swappable) drives. It looked like the best compromise for what I want (I want to be able to remove/replace/add drives -- I use both optical and hard drives via firewire), without the added expense of the 4-bay all-master enclosure with fully hot-swappable bays (since I don't really need to swap drives all the time).
Hopefully, this thing'll work.
One thing I was surprised at, though, was that there aren't any enclosures that use a single port for all drives inside. I guess that's to make sure that speed isn't limited by the interface, and I can always route everything through a hub, I suppose.
Thanks for your advice, anyway. It seems like there's very little choice out there in this realm, except for 2 or 3 companies that build everything themselves.