Update: Darren Urban spoke to Ken Whisenhunt on the matter. Whiz had this to say:
"It seems like you’d be hard-pressed to find a team that hasn’t been linked to (Roethlisberger interest)," Whisenhunt said. "At this time of year there’s no shortage of information and misinformation flying around; who teams are interested in drafting, who they’re not, who’s gonna be traded, etc. From our standpoint, it doesn’t seem to make sense to publicly comment on which rumors are fact and which are fiction but I can tell you there’s a fair amount of each."
In his weekly interview with Doug and Wolf on Sports 620 KTAR, John Clayton reported that the Cards did in fact call the Steelers about Big Ben. He did mention that he didn't know if the Cards even offered anything for Ben or if it even got that far, but just the fact that they are wondering has to make you think the Cards have some doubts that quarterback Matt Leinart can give them what they want out of the position. I personally don't think they will trade for him but you never know, crazier things have happened before.