Hi, I recently learned about Retropie and got a pi3 and got it all running out of a case, plugged into my big TV, and immediately thought - this would be awesome in a portable. And since I used to have Lynxs back in the day, I knew the case was pretty chunky. I was delighted to find people had already done that! So I've been researching, watching youtube videos, and figuring out which components I need to buy. My goal is to create a portable I can play, or plug an HDMI cable into and connect it to the TV, and plug a controller in the USB port and play it the way I play it now.
Cowdog360 your write up has been really helpful. Did you ever complete your version to run on AA batteries?