I think it comes with 1 adapter bracket.. and SSDs often come with brackets as well, check your SSDs
Indeed, this picture illustrations where it is installed: http://www.hardwaresecrets.com/fullimage.php?image=18466
Which is from this review: http://www.hardwaresecrets.com/article/SilverStone-Raven-RV02-Case-Review/789
I haven't really found much useful about what size of graphics cards the Antec 900/902 cases can hold, the figures which I have seen stated are 44cm, which I don't believe. It would only be possible IMO if, when you remove the HDD mounting system it is possible for the graphics card to extend beyond where the bays start, but to achieve this you would have to not use one of HDD cages.