I agree the photographs are brilliant comparrions, but take issue with the part about wanting it on a plate. Problem some have, like me who has not altered engines too much (repaints yes and coaches but I haven't taken to cutting too many engines), is that the engines are expensive to start to work on, or modern tooling in recent years has meant that detail changes have been incorportated and that its a case of waiting for the right model to be done with the right features. This I think is the case of the NER style smokebox, but I would think it highly likely it will be done in the future. Its not a case of can you do it, but a case of can you do it to the standard and finesse of the models that are made now, especially when your considering an upgraded or detailed model like the B1. If your not prepared to wait, or doubt whether your efforts would ruin it - then perhaps maybe you buy the model for what it is as its as close as youd get for the time being.
Meanwhile I am prepared to wait for the Hornby NER style smokebox, although I think Bachmann's B1 looks pretty close.