Agree on Hornby approach , probably meaning a J27 is likely. They do tend to concentrate on a region at a time. Hopefully we will find out in Engineshed sometime next year.
Also agree LN&WR seems to be getting left behind at moment. Maybe it's because there are just so many prototypes it's difficult to specify any particular one that would be a good seller. A Cauliflower 0-6-0 maybe, or a 2-4-0 which is something a little different. A large boilered Claughton maybe (would look nice in LMS maroon)
But of course the obvious area is Scotland , and the major difference is there are still preserved examples around .812 class 0-6-0 , 0-4-4 ,NBR Maude J36 0-6-0 . All could be modelled in pre grouping, grouping,early and late BR . And of course the Caley samples would look great in blue. Quite distinctive.