what you could do is play around with the widgets, but you are limited in the content you can select (e.g. you can change the box for the clock so that it shows sudoku, say, but it is not very flexible) - and until we get the source for the themes, we won't be able to modify the interface as we like. What you can do, though, is to install the layout of the older models (PB360, PB302), and modify the existing themes. We have all the resources to do so in the forum, but it requries a bit of work - if you wnat it exaclty as you like it. I have collected some instructions
here - and if you decide to go down that route, you should really read at least most of the sticky "Themes for Pocketbook" thread.
EDIT: unless of course this is not what you meant, and there is a simpler way!