Interesting thread. I agree with Blave that the instructor is a big part of the picture, and his confidence/paranoia ratio can be a bigger factor in time to solo than the student's natural ability. I was lucky to have a great instructor, very confident and good at judging how ready the student was. In reply to Banjo's comment about not having done advanced autos before an early solo, that really depends upon the instructor's syllabus. By my 8+ hour solo, I had done straight-ins, 180's, 360's, and he soloed me after we did autos from cruise and 50 feet altitude. These were all full touchdown autos, never had to do a power recovery until it was time to prepare for my checkride. Had the director of the school not been in the reserves, activated and sent over to the first gulf war, I'm sure it would have been 20+ hours to solo.
-- Bryan