Unless you really want to keep the 8" barrel as well, your best bet is probably to send your barrel to a gunsmith to cut it down to your preferred length, and add a new front sight, most likely a dovetailed sight, unless the gunsmith is able to slot the barrel for the original style sight. This would be a LOT less expensive than a new barrel, plus removing the ejector assembly and getting it installed in a new barrel can be a major pain with these guns (the ones I've had any experience with were extremely tight in the rammer slot, don't know if they are all that way). And you wouldn't have to ship the whole gun, just the barrel. Anyway, food for thought although you've probably already thought of it.
On the other hand, you could get really lucky and someone with a short barrel might want a long one!