http://en.wikipedia.org/wiki/PDMI
PDMI (Portable Digital Media Interface) is an interconnection standard for portable media players. It has been developed by CEA (Consumer Electronics Association) as ANSI/CEA-2017-A standard Common Interconnection for Portable Media Players in February 2010. Chaired by David McLauchlan from Microsoft, the standard was developed with the input or support of over fifty consumer electronics companies worldwide. [1] It is designed as an alternative to the iPod interface which was used exclusively by Apple Inc.[2]
And the rest of the tablet is just a screen. There aren't many other ways to design it.
http://www.engadget.com/photos/samsung-galaxy-tab-10-1-unbox...
Are you talking technically? As in the connectors and functionality are the same? If so doesn't that seem like a reasonable move considering third-party companies are building peripherals for that connector? If you mean it's the same shape, then yes, it's a small rectangle.
You are right. These are all obvious choices.