Are these local governments really more corrupt than the national government or do they just seem that way because they are so petty and ridiculous in their corruption? Stated another way, are you really arguring that corruption on the scale we saw in the recent financial crisis and its aftermath is really less dangerous than say the Blago spectacle?
You would seem to underestimate the importance of the latter part of your observation to a surprisingly large and dangerous degree. But on this we can perhaps agree to disagree.
My point is that if we expect state legislators to be our great defenders against an overweening federal government I contend we are putting our trust in a very weak reed.