It's a strange bit of history that the concept of an Apple tablet led to what we know as the first iPhone. It's a fact that Steve Jobs made mention of back in 2010, at an appearance at All Things D, realizing that Apple was capable of building a handset based on the technology it pieced together for a multitouch display. Now, thanks to Apple / Samsung court filings (you know that whole little kerfuffle between the companies) and digging by the folks at NetworkWorld, some early concepts for an Apple slate have come to light. The dates of the mockups are a little nebulous at the moment, but during his deposition, Jonathan Ive, puts them at somewhere between 2002 and 2004. Check a few more angles and a stiff case usage in the gallery below.
Update: Our friend Anand Shimpi of AnandTech pointed out that the first iPad prototype used a Pentium M processor. We sure have come a long way.
Update 2: BuzzFeed obtained some color photos of the gigantic prototype placed next to an iPad 2. Head over there to see more.