So corprorate666, I guess you are looking for a FFP which grants you lifetime platinum status.
Here I have some suggestions for you :
StarAlliance :
BMI : First you need 16,000miles to become a silver member, once done, you have to fly 38,000miles to get gold status.
And then you need 38,000miles/year to remain a gold member.
For being a gold member ten consecutive years, you'll get lifetime gold(platinum?)
BMI is VERY generous to business class and first class guests. (*2.0 and *3.0 each) So you'll need to fly only 19,000miles/year in business.
Asiana : First you need 100,000 miles to become a diamond member. (equals StarAlliance Gold) REGARDLESS HOW LONG IT TAKES.
Your status remains three years, and you need 40,000miles within those three years. I think it will be no problem for you even if you only fly economy and cannot concentrate on StarAlliance carriers.
Once you have one million miles, you have the lifetime platinum status.
Asiana isn't that generous towards business and first fliers, (*1.25 and *1.5 each) but once you achieved the diamond status, it's extremely easy to remain diamond until you get that lifetime platinum.
Asiana is recommended if you plan to get status at SkyTeam and OneWorld at the same time. Getting 40,000miles in every three years is really easy.
Lufthansa : You need insane amounts of miles and have to be over 60 years old in order to get lifetime status. Those Krauts must be kidding. I'll pass.
(Played too much "Company of Heroes" recently.
)
(To Germans : Es tut mir leid mit "Krauts". Im obigen Spiel, das Gespraech in Deutsch in der zweiten Mission ist falsch uebersetzt. "Dein Frass ist unter aller Kanone....usw")
SkyTeam :
Korean Air : Being Korean carriers both, Korean Air's and Asiana's FFP are quite similar. The only, but huge difference is that Korean Air grants you Elite status at 500,000 miles!!!! It's insane IMO.
On the brighter side, once you join the Million Miler's Club, it's a lifetime status.
Air France & KLM : 70,000miles/year for platinum. Ten years platinum, lifetime platinum. Enough said.
OneWorld :
I have no idea. You are on your own.
The decision is yours. I hope it was of some help for you.
cya