I've tried all sorts of liquid vegetable oil-based pastry recipes and hated them all. What I do now is make the plain pastry recipe from the joy of cooking, only substituting non-hydrogenated shortening (the last one on the page) for all of the fat (butter and lard or shortening). It basically works out to 1 cup all-purpose flour + 1/2 tsp salt, cut in 3.5 ounces shortening, add water to bind, refrigerate for 1/2 hour, use.

You could of course use normal shortening since it's vegan, I just like the non-hydrogenated stuff for health reasons.