Mileage from 2011 stickers:
35i: 17/25 (up from 15/21 for 2010 30i)
35d: 19/26 (same as 2010)
50i: 14/20 (up from 14/19 for 2010 4.8i)

The 35i is pretty darn close to the 35d. Major problem in US for diesel is that so many gas stations don't have any. That needs to change which won't be quick.

BMW will need the diesel 8 speed and/or 40d in the US long term if they want to stop the discounts on diesel engines over gasoline. Diesel will only continue to sell if cheaper to buy/run or the power/torque numbers open a larger gap from the 35i.

__________________
1995 BMW M3 (Track prepared)
2006 BMW 530xi (Wife)
2011 BMW X5 35d (Tow/Daily)