I came across these two sites while doing a web search and they seem to have some interesting products.
Muswell Models - a range of different buildings in OO and N gauage (which I model in)
Gramodels - range of kits of mostly military vehicles in the same scales including some of which could be easily bashed to make civilian vehicles.
Has anyone used either of these suppliers before and have any comments on the quality of the kits and service?