Here's the reply I received from Bethesda when I wrote them about this upcoming product. Best way to contact them and be sure they get your email, is to use the form on their site.

Hope this helps

Chiglet
----- Original Message -----
From: "Press2005" <>
To: <>
Sent: Wednesday, October 25, 2006 12:10 PM
Subject: RE: game_question
Knights of the Nine will be available as a download for both PC and Xbox
360 just like all our other downloadable content (DLC). It will be
available on Nov. 21. Knights of the Nine for download does not include
any of the previously released DLC.
In addition, a Knight of the Nine DLC collection for PC will be
available at retail that includes Knights of the Nine as well as all the
other DLC we have released to date, such as Mehrunes Razor, the Wizard's
Tower, etc. Unfortunately, it's not possible to release a retail
collection for Xbox 360 at this time, although it is something we are
working on with Microsoft and are hopeful that we'll be able to resolve
in the near future. So your only option there, for now, is to download
the DLC through Xbox Marketplace.
Thank you for your interest and I hope that this helps. Please continue
checking our website for updates.