ebay is still the best place for this,I think.
I visited Japan this summer,and I saw countless videogame guides and books in multiple book and gamestores there.
I cant remember exactly all the Suikoden stuff,but I would recommend Akihabara,with all the insane stores there.
Nakano was also nice,but I have searched other things there and did not pay attention to Suikoden.
I also made a video,while visiting the "Super Potato" store in Osaka,which is the best retrovideogame store,I have ever seen.make sure to check it out,if you are in Osaka(DenDen Town,Nipponbashi):http://www.youtube.com/watch?v=jYggHs2j_u8
Super Potato stores usually sell second hand stuff(in awesome condition),and they have a large stock,so I would ask there.maybe they have it.
I also saw a gigantic "Mandarake" store in Tokyo(Akihabara).they usually have that kind of stuff.maybe they have your book.I made a pic from the store: