Having been inspired both by the helpful comments from you all and by the superb quality of Gandwarf's maps, I thought I would try out one myself. Being no artist (more of an amateur dabbler), I thought I would try to remodel Highmoon. I started by printing the one from the Forgotten Realms Atlas and then added my artistic license to it. With the release of 4E, it also gave an opportunity to make the map slightly different from the original.
I am not sure about the choice of houses but I could not decide which ones I liked best. I have played about with shadows and blur to see what effects I would get, but I have only just started with CD3 and some of it is taking awhile to learn!
Thanks to Gandwarf for providing the motivation!
Out of interest, I assume that it is OK to base maps around FR stuff as they are for my own use? Should I put 'all copyrights acknowledged' on them or something?