Can Hairpin support line-spanner-interface?

[Mark Polesky]

Hey guys,

Could the Hairpin grob be changed to support the
line-spanner-interface?

If not, is there a way to fine-tune the left- and
right-endpoints of Hairpins independently from the
NoteColumns?  

Does Hairpin inherit the X-extent property from
DynamicLineSpanner?  If so, how does a user adjust
something that is hard-coded?

I'm afraid my recent absence from developer-land is
making me look more like a casual user, but maybe
that's a good thing: I'm seeing how confusing some
things really must be for the novice.

Thanks.
- Mark