I think that we need something more precise, than "unfinished". Such a topic could cover every model and thus the idea of GB would be lost. Just think, that buying a model you certainly open the plastic bags, look through the instruction, check your references - is it not starting a model? My point is, that every model we buy is already started. It is so with me, at least.
The concept of the current GB, just about to be closed, was perfect. Precise and simultaneously quite wide. I would suggest something of similar format. For instance: British Scouts, or scouts in general, or from a selected period (e.g. 1918). Pfalzes sounds fine, but gives a little bit limited choice. Just my 3 cents.
