Alongside editing graphical resources, you can customize the wallet interfaces to define your own. Most of the dialogs in Bitcoin-Qt are created based on the Qt framework using Qt designer. The resource files corresponding to different dialog forms are editable files with .ui extensions and are located under src/qt/forms.

If you're not keen to use Qt, you can alternatively design and write your own graphical wallet in other languages and tools such as C#/WPF, and communicate over RPC with Readercoin's RPC API.