I found these online but have not tried them:
The second link I have ordered other items from them and have always received my shipments very quickly and well packaged. It looks like the reviews for their vegan pudding mixes are mixed.
There are quite a few vegan recipes on here for homemade puddings. I tried a few tapioca ones, and I do my own chocolate pudding which is quick and wonderful. I veganized the following pudding recipe and it turned out very thick and rich and can be made in ten minutes or less:
The only change I made was using almond milk instead of regular. Soymilk would work well too. If you still use milk then you could just use the entire recipe because the milk is the only item not vegan (and the sugar unless you use beet sugar or some type of organic raw sugar). It doesn't get much simpler, although it isn't the healthiest. You do have to be careful not to overcook it though or it will get lumpy, but otherwise it's good.