You might want to look into a product called Smart Balance. It's a vegtable oil spread with no trans fats. It comes in a couple of varieties, a light and a regular just to name two. The light variety contains flax oil and the label states that it's not suitable for cooking while the regular is ok for cooking. I've used it in some granola bars that I like to make.
While I don't know if it will work for pie crust, a mixture of unsweetened applesauce and canola oil can be used as a substitution for butter. I've experimented with this as a way to cut down on saturated fats. You'll have to try out different proportions to see how it works. In my granola bars, I've used a 50/50 mixture and a slightly smaller total volume than the typical butter usage, i.e., combined volume of applesauce+canola oil = 86% of the butter volume.