Some Input regarding prospect work for a wordpress theme

I’ve made some preliminary contact with a client with regards to a custom theme that they want done for wordpress. They want something similar to this:

I made a preliminary review and audit of the theme in preview mode and it contains around 46 page/post templates. If I were to do something similar to this, I’d estimate that it would take me about 2 months to finish to account for the research, implementation and testing (Very rough estimate). I was wondering if anyone here has had any experience creating a custom wordpress theme this complex, what would you charge, and how long would it take you?