...serious question: anyone ever hear tell of a 9 hour De Laurentiis version running around out there, somewhere?...
No. The rough cut without completed effects was initially about four hour long. Lynch intended to cut that down to three hours, but was forced to cut it down much further. There's a 190-minute version that was cut together for television without Lynch's participation or approval. That's the longest version of the film available. There's also a three-hour fan edit.