It's not just the 4000D, this would allow it to fit the 4000T and leave four Zorro slots available. A bit more research and a few more options on these PCI extender thingys and you could be on to a winner. I'm sure there are many like me who'd like PCI but just aren't going to mess about with new casing and don't want to loose Zorro slots.
I must say I'd be very interested in a kit.. !