you have all the physical adapter necessary to make the connections, however... the ACD is not DVI-I... it is DVI-D. DVI-I and -D are not different formats of DVI, it merely states what type of signals they will accept.
DVI-I has the TDMS digital input and also has an RGB analog video input (on the pins that look like a cross and the 4 surrounding pins)
DVI-D only support the TDMS digital input. Most DVI-D displays also have the physical slots to accept the analog pins, but this is only to prevent cable incompatibilities.
When you get an adapter, it does not convert digital to analog or vice versa, it only allows the appropriate pins to get connected to the correct pins on the other connector. In short the ACD cannot accept a non-digital source (HDMI or DVI). I have heard rumors that MS does support digital output, but there is no product yet that breaks it out from the console. I have also heard rumors that there will be some form of digital (HDMI likely) to coincide with the HD-DVD release, but no one knows for sure if this means that only the DVD playback will be supported on the HDMI or if it will be both gameplay and DVD. The other problem that you face is that the 30" ACD only supports a small handfull of display resolutions. None of those happen to be equivelant to an HD signal... like 720p (1280x720) or 1080i/p (1920x1080). that might create another problem... as the XBOX can definitely not do the 30"'s native resolution. it is up in the air if it can even do one of the supported (but crummy looking) rez's like...
1280x800
1024x768
1024x640
800x600
800x500
640x480