The juiciing attachement for my Champion Juicer, ours has the commercial grade motor so should be able to grind a lot of wheat for us if need be.
I have a Champion Juicer there are the two attachments that came with my machine, I have a juicing attachement and a grain grinding attachment. I have heard that if you have a Kitchen-Aid mixer of 500 watts or more you can use their grain mill attachment but not to try it on the smaller mixer, which is what I have!
You could probably use a regular coffee grinder to grind wheat berries I'm just not sure how long it'll last. I have an antique coffee hand grinder and it grinds wheat quite nicely.