There was at least one vendor (a Dan Hoffman from Sorrento, FL if I recall correctly) at the recent Florida Woodturning Symposium who demonstrated an off-center turning chuck. It had adjustments and markings to allow great precision and repeatability, including the ability to adjust a small amount in a negative direction from dead center. (IOW, opposite the normal positive offset while remaining chucked.)
I don't recall the capacity or many other details, but I believe the cost was well below $200. With no web site, he offers contact via email, which I will pass along (rather than post) if sent a PM or email via the forum.