Weiland and Jimmy Chamberlain would be cool, he's an awesome drummer. Personally, there are a lot of musicians I'd like to see Scott collaborate with but #1 would be David Bowie. First of all, I think Scott would obviously LOVE the experience and secondly, I'm not a crazy fan or anything but I do really like David Bowie. He's probably my second favorite solo rock artist after Weiland.
I've also thought it would be cool if Scott did some sort of collaboration with either Jerry Cantrell, Chris Cornell, Eddie Vedder, or anyone else who was/is in another big 90s band. Not like a major supergroup like Velvet Revolver, but rather one that is made solely for the music and not with the goal of being a big hit.