You can look up the old twa.com site through
www.archive.org. I was looking through the Aviators brochure the other day at the elite qualification and it looked like a great system. I started flying in the Ozark days, then TWA, and now AA - but TWA was out of business before I ever had the annual miles to be elite.
One thing that seemed really nice was that you could make each of the elite levels on spending (5k,10k,20k - I believe) in addition to the mileage. So someone who flew infrequently but bought premium fares would still be rewarded for their business.
Anyway, I'll miss TWA. I really enjoy flying the TWA 757s that AA inherited. Their F cabins are much nicer than the filthy, old AA 757s.