Probably the most challenging painting that I did for my Christmas commissions was this one. 
[sorry for the awful photo]
It was challenging first because the photo that was provided was from the 1950′s which meant it was extremely small, bad quality, and horrible color. Secondly, the reference photo was of the house in the dead of winter. Dead trees, inches of snow on the ground, etc. The woman who asked me to paint it said she wanted it to be a summer photo. She sent me a lengthy email describing the placement of trees, bushes, and flowers; she also told me what kinds of flowers were in each planter and flower bed. I took it from there and although it was a stretch, I’m pretty happy with how it came out. She was beyond thrilled and said it looked exactly how it was supposed to…glad to hear it.
Love this. This is what home is supposed to look like. (Random, but for some reason, your art blog is missing from Reader. Will have to fix that.)