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I received 5 replies.  Uses mentioned are for Flaxseed(3),
Rice(2), Nuts(2), and Seaweed(1).  The responses are attached.

Gordy in Raleigh
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I have a Braun electric coffee mill that I use for grinding flaxseed.
It was pretty expensive, about $80, but it does a beautiful job of
producing a mealy-like texture, but if I try to grind it finer, like
for flour it gums up. This might be due to the oil in the flaxseed.
Had not thought of using it to make flour from other foods until I
read your post. Will be curious to see what you find out.
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The only thing I grind in my coffee grinder is flaxseed that I use
in a recipe for granola
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I grind my rice and it is wonderful....I also grind seaweed and
nuts......a wonderful little machine.....
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I used my coffee grinder to grind brown rice into a baby-cereal
texture when my son was doing baby food.  It was pretty close to
flour, although if I were making bread I might have soaked the
grain in the liquid (like one does with cornmeal).  These little
grinders also do a good job on nuts.  The only issue is the little
plastic cover on the grinder took some nicks and got horribly
scratched.  If your grinder has a metal lid, you should be fine.
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I received two coffee grinders for wedding gifts. I use one for
coffee and the other for all other things. Mainly I use the other
for flax seed. Whole flax seed will keep very well on a shelf but
ground flax seed does not and must be refrigerated. So with the
coffee grinder I can grind just a little to add to my breads,
pancakes, muffins etc.

I also found a recipe in one of Bette Hagman's book for Popcorn
bread, but the company that made popcorn flour discontinued it,
so I am thinking that popcorn could be ground in the coffee grinder.
I haven't tried it yet however.