We've lost count of the number of times seemingly crazy technology has found its way into everyday hardware years down the line. Come to think of it, there have been some whacky hardware prototypes that have turned into must-have technology - just imagine what a Tablet PC owner would think if you could have put an iPad in front of them way back in the mid 1990s. Technology changes and often ends up making our lives better further down the line, and that's why we're so excited about the invisible iPhone concept we just spied over at Engadget.