It's not insane to use stored procs, although I use them in conjunction with SSIS. The crazy part is the five minute update. Data warehouses have a place in operational reports, but five minutes is really too frequent. As someone has already pointed out, that sounds more like a task for a dashboard. Warehouses are used primarily to discern trends, both long and short. Ultimately you have to do what your boss wants, of course, but you might what to understand what the intent is.