Tai-Pan

Last night on Turner Classic Movies, I saw a trailer from the sixties called "Lion Power" about all the big projects audiences could expect from MGM in the months and years ahead. Included among them were clips from "Far From the Madding Crowd" and "Where Were You When the Lights Went Out?", plus mention of "Where Eagles Dare" with Richard Burton (not mentioning Clint Eastwood, as perhaps he wasn't signed yet), "Ice Station Zebra", and "2001: A Space Odyssey" with very early-form artwork of its making. Among the many films mentioned in passing near the end of the trailer was "James Clavell's 'Tai-Pan'", yet no earlier version of the film was ever made. Just how long was this thing in the making, and what casts were potentially involved at different times? It would be interesting to see the planned history of such a movie that took so long to finally get made, bad as it reportedly is.