When I was reading Articles of the Federation,
I was hoping there would be maybe a passing reference to the old Earth administration of President Josiah Bartlet, but it was not to be.
I wouldn't mind B5 being integrated into ST continuity. Farscape could also fit in. Andromeda could be the far future of the Federation.
And I'd definitely go for a ST/Highlander crossover!
Stargate has established such a different set-up of the universe that any crossover would be an Alternate Timeline type of story, and the threat of a big red Reset button lurking on the last page would spoiling reading for me.