At the time of his untimely death in 2009, Peter Jones was working on a book about building model buildings for garden railways. This has now been completed by his daughter Kes. I haven't seen it, but I'd put money on it being worth every penny - certainly top of my wants list.
http://crowood.com/details.asp?isbn=9781847972729&t=Making-Model-Buildings-for-Garden-Railways
http://crowood.com/details.asp?isbn=9781847972729&t=Making-Model-Buildings-for-Garden-Railways