I've added this paragraph to the first post:

"What happens when Lufthansa takes over BMI and closes Diamond Club?

It seems likely that Diamond Club will be closed within a year of LH's takeover in January 2009. At this point, it seems likely that BMI credit card holders will be migrated to the LH Miles & More Amex or Mastercard.

You may want to apply for the Lufthansa M&M card NOW. Whether or not you have a Miles & More account already, you WILL have one when your Diamond Club miles get transferred! The LH Amex also comes with 6,000 free miles to get your started - and its unlikely that you will be able to take advantage of this promotion once your BMI card becomes a M&M card automatically, as you would be classified as an existing cardholder.

You also earn 3 miles per £ for the first six months of the LH Amex card, instead of the usual two. This opens up an additional bonus miles opportunity, whereby in the sixth month you make a massive purchase of fully flexible flights (£10k worth if you have a £10k credit limit) and then immediately refund them after the month end. You should gain 10,000 miles for nothing, since the purchase would earn 30,000 miles but the refund in month seven (no bonus miles anymore) would only remove 20,000. I will let you know if this works in March 2009!"