As much as I love SG-1, it’s kind of a shame. Combining the two would’ve made for an epic scifi duology. Maybe in an alternate timeline. ;)

Googling around, there have certainly been rumors for years to the effect that ID4 was repurposed from a draft Stargate 2 script, but I can’t find anything solid one way or another.

Isn’t there also a Stargate connection? As I recall, the original ID4 was planned to be a sequel to Stargate where the aliens came to Earth in retaliation for Ra’s death. Jeff Goldblum was supposed to be Daniel Jackson, etc. But the studio had the rights and elected to make a television series instead.