Greg I think you've got the engine's rpm limit and the turbos function a little crossed up. A turbo will not let an engine rev beyond its design limits. What it will do is pack a denser charge into the engine at any given rpm and therefore make more power than if that same engine were naturally aspiriated.
So by using a cam that has mostly bottom end and running a turbo you will add to the upper end of the cams range if the turbo is set up that way. That makes your assumption of more power at top end correct but it does not override the cams rpm limits and let you rev freely to some excessive number. If the sum of the moving parts restricts the turning to 5000 rpm no turbo in the world will change that and let it run 6000 or 7000 rpm.
Mike