maximillianos - 3:31 pm on Dec 28, 2010 (gmt 0)
After doing some further research I found this article:
It seems to agree with my tests above that the canonical tags are not necessary.
I tested this theory by doing a search for "wikipedia mobile" and browsed their mobile site. Viewing their source you will see they don't use canonical either.
I typically think of Wikipedia as the standard when it comes to stuff like this. =)