Images of the original iPad prototype surface
SlashGear

Images of what could be a prototype of the original iPad from the early 2000s have recently surfaced. The said images come from documents used in the ongoing patent battle between Apple and Samsung. They show a device that is almost similar to the original iPad launched in 2010 but with a thicker body. 

What You Need To Know:

- Apple started working on a prototype of what will later become the iPad as early as 2002.

- Based on the deposition of Apple Senior VP of Industrial Design Jonathan Ive, he remembers seeing the prototype sometime between 2002 and 2004.

- The prototype has no physical Home button but includes a bottom slot that could be the precursor of the 30-pin connector port found on the iPad.

Other sources

My recollection of first seeing it is very hazy, but it was, I’m guessing, sometime between 2002 and 2004... - Jonathan Ive  
I’ll tell you a secret. It began with the tablet... and I thought, ‘my God, we can build a phone with this!’ So we put the tablet aside, and we went to work on the iPhone. - Steve Jobs  
TechCrunch
Behold! The Early-2000s iPad Prototype That Started It All  

In December 2011, Samsung deposed Ive in relation to a patent case. The deposition is a goldmine of interesting facts about the growth of the iPad and its slow metamorphosis over the years. He recalled, in the deposition, that he had seen iPad prototypes as early as 2002.

Engadget
iPad prototype renderings from early-2000s revealed in Apple / Samsung court filings  

It's a strange bit of history that the concept of an Apple tablet led to what we know as the first iPhone.

Other
iPad prototype from early 2000s revealed in Jony Ive deposition
SlashGear
Original iPad prototype photos appear via Jonathan Ive  

It appears that as early as 2002, Apple had been working on what would eventually become the world’s most famous tablet computer: the iPad

Images of 10-year-old iPad prototype surface during patent trial  

Had Apple (AAPL) not managed to radically revise its early tablet designs before finally launching the iPad in early 2010, the tablet market would likely be in a much different place right now.

Mashable
The Earliest Photos of Apple’s iPad Hit the Web  

Apple may have debuted the iPad in April 2010, but according to newly surfaced photos, the company started working on a tablet prototype in the early 2000s.

Android Central
Early iPad memories and prototype revealed, thanks to lawsuits
Other
Image of an early iPad prototype surfaces
Tech Radar
Photos of first iPad prototype revealed
Other
Mega-iPad prototypes revealed in Jony Ive's 2011 deposition now in color  

Hefty. Ample. Zaftig. An iPod hit with an Engorgio Charm. Pick your adjective and go with it, because this honest-to-Ive iPad prototype was just plain big. It looked like a chopped-off MacBook's top half, but it probably wouldn't have seemed out of place on Batman's bedside table.