In the early 1980s, noted industrial designer Hartmut Esslinger began working with Apple where he and his consultancy firm "Frog Design" helped shape the look and feel of Apple products for a number of years. Most notably, Esslinger is credited with shifting the aesthetic of Apple computers from beige to the once-ubiquitous Snow White design that graced a number of Apple desktops beginning with the Apple IIc.
In addition to influencing the look and feel of Apple's product line, Esslinger during his tenure at Apple helped develop a number of interesting prototypes across multiple product lines that never made it to market. Just last week, we highlighted one such product, a "smartwatch" Esslinger designed in the 80s. Not to be outdone, Esslinger in 1983 also protoyped an Apple fliphone (viewable above) that was ridiculously thin by even 1990 standards. That cellphones nearly two decades later would so closely resemble Esslinger's 1983 prototype really speaks to his vision and design prowess.
Below is another take on a mobile phone from Esslinger.
As a quick aside, if you're interested in reading about the design philosophy that permeated through Apple's product lineup in the 80s, make sure to check out Hartmut Esslinger's book "Keep It Simple: The Early Design Years of Apple."
Earlier today, The Verge posted a number of additional photos from Esslinger's book that many will likely find of interest. As a quick example, here's a photo of what appears to be a protable laptop/tablet hybrid.
But enough about interesting Apple products that didn't ship, here is an actual Apple tablet from 1979 that did ship. Note the presence of a stylus as the mouse had not yet been brought to the mainstream with the Mac. The tablet worked by mapping designs on the tablet to an accompanying Apple II. Dimension and price wise, the tablet checked in at 15.5 inches x 15.5 inches and came with a $650 pricetag.
One interesting piece of Apple trivia is that the graphics tablet below ran one of the first computer paint programs, titled "Utopia Graphics System." Also interesting is that the program itself was designed by noted musician Todd Rundgren.