This kind of sent me for a loop when I read it. Of course, it's a brilliant idea, but what i have heard about the Cognos security model makes me feel somewhat bewildered.
Clicky! Cognos + Blackberry = Headache!
I wouldn't see that being much of an issue. Wirelessly push the app to the handheld and MDS should allow it to connect to whatever database it needs to. I know nothing about Cognos but if they release it for BB and BES I would assume they would test it and have some set up instructions.