FoV is too large to be released as DLC on the Xbox, as Larian had originally intended to do.
Funny really considering you can download full retail games on Xbox Live. Pretty sure Dragon Age Origins: Awakening is available on Xbox live aswell as some other game expansions which are quite large in size (Lost and the Damned?).
Saying that Microsoft always seems keen to bend their own rules for some of the larger developers out there.