Thought about a shark fin?
Skyliner - Briefly but I don't want to drill into the roof or, indeed, add another 75mm or so to the height. Even when I eventually get around to fitting a solar panel, I'm looking to avoid drilling if it's possible to tuck the cables under the back of the pop top and through the gap at the top of the canvas. That said, I know bugger all about fitting solar panels and don't know whether or not that's a practical proposition.
I have mine at the bottom of the windscreen in the middle. Located at windscreen / upper dashboard location. Good reception from my Kenwood 8109 head unit.
BoroBoy - Have you got a heated windscreen? My understanding was that a screen mounted aerial wouldn't play nice with them.