I'm sure someone will have a better answer eventually but I would do one of two things. First I would call Gibson, or a large Gibson dealer, and tell them your model and they will have suggestions for alternate cases. Secondly, I would take the guitar to a large-box store (if one is close enough) and personally do a fit with the guitar. If those two don't work for you I would then give the measurements of the guitar to a guitar case manufacturer (several on the web) and they will tell you which case is most appropriate for that model/measurements. Happy hunting.
Martin-D-41,Custom Shop OM-28V,000-28EC,D-222 coming, Gibson-J45, J-15, Southern Jumbo, Voyage Air, Epi .... tried (almost)everything.