I did some thinking on what they would need to do to bring D3 to console.
Rework the control scheme - a simple enough feat with Diablo 3's stripped down user interface. Have the left stick move the char, the 4 face buttons act as your 4 active skills with the left and right trigger handling your primary and secondary attacks respectively. You will need a custom "interact" button so either of the bumpers could do that, the remaining bumper could open the inventory. Back button could handle the skill menu.
Reword the inventory so you can equip with the push of a button.
Remove type chat completely
Probably do away with the RMAH
A whole lot of minor balancing tweaks that would just come from testing.
Change the save system so it saves to the local HDD instead of the cloud.
If it does happen I think we are more likely to see it on the PS3 than the xbox, simply because Sony is alot more open with their platform than MS, steam on PS3, Counter Strike GO's cross platform play etc. And unlike the PS3 the xbox doesn't have any internet required games (AFAIK anyways) where the PS3 has DC Universe, War Hawk, M.A.G etc which leads me to believe that MS requires their games to have some sort of off line functionality, for the time being anyway, with online as optional. I guess if Blizzard was cool with this then having Diablo 3 on Xbox would be more plausible.
Probably on PS3. Just like Dust 514. I assume blizzard would want to use their own servers and as far as I know Microsoft doesn't allow that on Xbox 360?