Maybe Hornby still have the Triang design references for the original, albeit that RTR model was somewhat compromised for its contemporary train set market and production abilities. On the other hand if Bachmann were to be convinced of a viable TT120 market they already produce excellent models of the original in OO and N and a switch to an in-between scale would be fairly simple for them to do, and it would remain a talisman model for them for many years.
I am still somewhat surprised that we have not seen any mention by of a TT120 Brighton Belle of which we can have their own branded OO and Arnold N Gauge offerings. I find this particularly odd as Pullman is a bit of a Hornby 'thing' that already features prominently in their TT120 range.
And I for one would buy any of the Blue Pullman iterations, but only in Nanking Blue.