I agree that a turntable feature is needed here. It dosn't make any sense for use to upload small videos to Youtube or Vimeo and then create a link for viewers to transfer to.
This cumbersome process might have made sense when file storage costs were expensive and the code for displaying a standard *.mpg file was a bit tricky.
But neither of these are true now. I own my own web site and it has been trivial to host videos in *.mpg file format on it for the last eight years. (Although my vidoes are for the purposes of displaying animated liquids, rather than a turntable view of the models.) CG Trader should be able to do the same without killing a web designer in the process.
Personally, I prefer to purchase models where I can take a good look at them from various angles. And all rendering software that I use create turntable views. A turntable view is so very common now - why not host this feature?????