Restricting Bone roation with constraints?

I am tring to find a way to restrict a bone to rotate only to much on a certain axis… I was told I can do with the some weird way of setting up contraints… is it possible?

not really

you can do some interesting things with IK and track to constraints, but it isn’t really useful for constraining direction (or motion).

I would expect such a constraint to come soon because of the demand (and theeth publishing a howto make a constraint)