Still cant find the pictures but I have definately seen it somewhere and it looks nice.
I've seen this done before (steel silver, black roof) and it didn't look quite right - it made the car look 'stubby' or somthing, can't quite put my finger on it.
Not sure if its what you mean CJ but I thought it made the car look like a convertable. (from the front anyway) The black blended in with the dark background, looked as though there was no roof there. I didn't like it straight away but the more I looked at it, the more it grew on me.
As no pics of a car like this can be found it would be quite unusual if nothing else. That in itself is appealing (IMHO), as it would be a bit different to the norm. I say go for it, if in the end you dont like it you might be a few quid out but atleast you could always change it back, or alternatively paint the whole car black.