[Update 11/16/13] The old link expired but there is a new link which is supposed to work through 12/15/13:
Landing page (Lufthansa) for the new 50K offer
Landing page (Barclays) for the new offer
[Original Post 5/8/13] Barclays Lufthansa Miles & More MasterCard normally comes with a 20,000 miles signup bonus. However, there is a special offer open to public that gives 50,000 miles: you earn 20,000 miles after the first use and an additional 30,000 miles after spending $5,000 within 90 days. The $79 annual fee is not waived for the 1st year. The T&C says that you will be first considered for the Premier World MasterCard, but if you don't qualify you may receive the Platinum MasterCard. This is typical with Barclays cards. However, no matter which version you receive, you will be able to receive the full 50,000 miles once you spend $5,000 within 90 days.
The landing page for the 50,000 miles offer (dead)
We have no intention to review this credit card product as of now, but will summarize its features here (Premier Wold MasterCard). You earn 2x miles on Lufthansa, and 1x on everything else. You will receive an annual economy class companion pass upon 1st use of the card as well as each anniversary. Since Miles & More is a SPG transfer partner, for general spending you'd better use Amex SPG since it returns 1.25 mile per dollar spent.