This is a figure I had planned ever since I saw the "Night of the Doctor" minisode, and it was icing on the cake when they released an alternate 8th doctor head with the War Doctor figure. I just needed a body to work with...
After looking at McGann's promo shots and any Doctor Who figure bodies that might work well, I landed on the 5th Doctor "Castrovalva" figure (4th Doctor "Keeper of Traken" figure would work, too). I added laces to the boots with light epoxy and thread. Also created a belt and buckle with epoxy then painted the vest, pants, and boots varying shades of brown/grey.
The original 8th Doctor figure's coat seemed the best option for this custom. It was quite a task to find one of these for a price that wasn't outrageous, but I was blessed to win an ebay lot with the 8th Doctor for a great price. I originally intended to use the 8th Doc's arms, however it would have been more work to get the joints to connect properly to the 5th Doc's body. For this reason I decided to just paint the existing arms. I also had to cut the back off of the vest to make the coat fit. I created a joint to attach the head and made the scarf from real cloth to complete the basic figure.
The TARDIS in the photo is a quick custom-painted 8th/War Doctor's TARDIS from the "Night of the Doctor" and "Day of the Doctor" episodes.
Thanks for looking!