I've launched this project on Kickstarter that hopefully interest some of you:
For more info and pictures: https://hackaday.io/project/164930-portable-retro-game-console-with-79-inch-display
I know it's a bit more expensive than other Raspberry Pi-based consoles.
But the biggest reasons for that is the high quality IPS display and 8000 mAh battery.
All kind of support would be greatly appreciated.
If you have any questions, I will try to answer them as fast as I can.