Gina, here are a selection of night time shots that might work. I previously used number 3 or number 4, I can't recall which. Let me know which if any you want, and I'll place them.
Also, it's worth remembering that the font page banner was meant to be consistent across all assets, FB, Youtube Channel, G+, Twitter and web, so having a very non-specific image there isn't such a great idea in my opinion (i.e. it should be a strong imaged focussed on the core biz).