I have made some progress on the widget. Currently it shows the last 5 books read, where read is that a reader app was launched from CC. The following screen captures show it in 1x1, 1x2, and 2x2 boxes. Adding more on the Y axis shows more books. Adding more than 2 on the X axis shows more black borders. This is a list view, so it scrolls vertically.
1x1
1x2
2x2
The widget refreshes automatically whenever you read a book from CC or update metadata by connecting as a wireless device.
Added to yesterday's progress with shortcuts: shortcuts are created from book details. The menu looks like:
When you tap a book in the widget or in a shortcut the book opens in the default reader app without showing CC at all. If there isn't a default reader app for that format then you get the following:
For various reasons that for me are unexplicable, if you open a book from a shortcut or a widget then CC is removed from the task list. If you tap a CC shortcut then it starts where it was, so I think that this isn't a very big deal.
None of this is available on Android < 4.0 (Ice Cream Sandwich) or on Amazon devices.
I am going to let this sit for a few days to see if there are any more comments, then after a bit more testing release it to the CC beta group.