I was recently on this board asking about pie delivery in Marin - the system has eaten that thread, but I wanted to update because I was so happy with the result of my search.
I ended up with Delicieux Fine Desserts - no idea how I found them, but I'm glad I did. I believe they mainly do farmer's markets, but they delivered a mixed berry pie to my friend's house on Christmas Eve for a very reasonable price (less than half of what other bakeries quoted me), and the pie was the hit dish of Christmas Eve! Of course I tipped generously ahead of time, that helped with the Christmas Eve delivery but I'm sure the quality is always the same. So there ya have it, a delicious pie in Marin County that can be delivered to your house.
Delicieux Fine Desserts