No, it doesn't have SLI or Crossfire cables. As I said you'd have to use the adapter but I really would advise against using it for X1900 Crossfire as it only has a 35A 12V rail.
For that I'd suggest something along the lines of the Corsair HX620W.
Phenom II 940 Black Edition quad core @ 3.5Ghz
2x1 gig OCZ PC26400 Platinum, 2x1gig GSkill PC26400
Upcoming EVGA GTX470
Some other stuff,
Even more stuff,
If the automobile had followed the same development cycle as the computer, a Rolls-Royce would today cost $100, get a million miles per gallon, and explode once a year, killing everyone inside. --Robert X. Cringely, InfoWorld magazine