I make pudding at least once per week! I just get this pudding mix from
the grocery next to my house (50cents per packet). It is made by a
company called "Oetker" & although the website is in German, it is made
in Canada (http://www.oetker.com). I have no idea what the site says - I
don't speak German. I'm not sure if you can get it where you are, it
doesn't have any dairy or sugar added.  I just use soymilk (I use the
light stuff otherwise it is tooo creamy) and add as much sugar as I
like. It is sooo good. It doesn't taste as good cold though. I would
imagine that any pudding/ custard powder would work the same way, as
long as it is the cook variety, not the instant cold pudding variety.
There must be this sort of thing over in the US.  It is mainly just
cornstarch + whatever flavour you like, which you just barely bring to a
boil till it thickens. I always get the strawberry. YUM - you can't
taste the soy at all.
Good luck!
-Bronwyn