I know this is an old thread, but I definitely watched the first 5 seasons of SG-1 in HD and widescreen on Showtime. Perhaps it was upsampled from film, but it was excellent quality. I watched via my C-band dish and the HDD200. I stopped watching when SG-1 left Showtime and started running on Sci-Fi, primarily because the picture quality sucked and it was in 4:3. Now sure how Showtime did it but I've got to believe the content they used is out there somewhere and should be easy to author to Blu Ray.
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