It has been wished for as long as DS has been on Sci-fi, including its inital run that they would do a DS marathon, which has since become known as a chain reaction. However that has never happened and probably never will. While Sci fi seems to know DS is popular with its fans, they still don't see it being as marketable as Star Trek or Stargate SG1. Part of the problem is the fact that the series is a continuing drama and I guess they feel that it would be unfair to air a small grouping of shows and leave people hainging, who might not get the chance to watch it at it's regular time.
However, I can see them doing a Chain Reaction of the 1991 mini series. That would be interesting to revisit this off shoot of the original.
Raholt
