Some more progress. I will never finish this if I try to do it all by hand. I wrote and applied some selective photoshop actions to give the roof tops more depth. I think that they worked fairly well although I notice that some of the buildings I thought were selected, have been missed and I accidently created a bunch of 'transparent buttons' in odd places, but I think I managed to get rid of them.
Anyway, here is the latest installment.