Hornby missed the bus with British N gauge, and ditto 0. The other players are eying what Hornby does. I suspect Bachmann aren't really interested given the range of scale/gauges they are already covering (and their scarcity of internal manufacturing capacity which has lead to the whole EFE venture), Dapol are probably in a similar position. Heljan are the most likely to dip a toe in when the water is a little deeper after being totally gazundered on their initial foray, and there seems to be some interest from Revolution staff at least. Rapido might surprise us, but I think we might see some models from Sonic as commissions down the line.
The big model for Hornby will be the Class 66 as that must be appearing under the Arnold brand for the European market in due course, which means we should see some of the more obscure (otherwise) UK variants being produced.