I'm looking for the absolute cheapest way to get the Star Alliance HON circle status. For that you have to collect 600,000 status miles in two calendar years. I don't care about long layovers or a lot of different stops. I also do not want to visit the countries I travel to, but just get this status.
I'd say your question is best suited for the gurus over at Flyertalk, who specialize in wrangling frequent flyer miles and the like. Take a look at the Miles and More forum, as well as the mileage run forum (which is their term for taking special trips that maximize mileage earned for minimum cost).
However, if you're willing to settle for slightly less status (no first class terminals in Germany, for instance) consider obtaining Star Alliance gold status on Aegean Airlines for significantly less cost—only 20,000 miles if I remember correctly. This will allow you priority boarding, lounge access, luggage tags, etc. for less than $1000 in flights if you plan it correctly. Look at this thread on Flyertalk for more.
To get the HON Circle Status there is only one way: flying, flying, flying. As of this September only flights in Business and First Class will earn you HON Circle Miles and keep in mind: you have to fly with Lufthansa, Swiss, Austrian or their affiliated companies (Star Alliance other than that doesn't count). Check out the program at http://www.miles-and-more.com/online/portal/mam/de/program/information?nodeid=2536038&l=de&cid=18002