WordPress Book Exchange Plugin Equivalent?

1. Custom Post Types (there are several plugins in the repo for that)
2. Custom Meta Boxes/Fields – a good library is the »RW Meta Box« set of classes
3. Extend the search – there are several answers that show you how to do this in the [tag:search] archive.
4. Role Management: IMHO »Members« does the job best + it’s well coded.
5. Reducing the interface – I got an alpha stage plugin called »WP Strip Naked« for this. ¹⁾

^{1) If you want, you can just take the parts that you need. If you think it’s a nice idea and maybe need it more often, just fork it and send a pull request. Happy to accept any cowork.}