The Sony Blog (Japan) has been updated with interviews with some of the team responsible for designing and building the PS Vita and its software. They talk about the oval design, the placement of the analog sticks, the screen - its easier to translate the page in Chrome to read it and get the gist, but a couple of the more translatable snippets include:
"There were many ideas about the logo, I decided to use the same font for the PS3 and get a sense of family."
"The screen also has a very wide viewing angle to it, and I think the best combinations of gyro and acceleration sensors. It does not have residual delays and there is no problem (with movement) as I can play while moving the body."