Gathering some info, here's what I found online:
The Gameboy, GameGear, and Snes ran on a CPUs at below <5Mhz.
Sega Genesis/Mega Drive runs at <8Mhz
The Raspberry pi zero runs on 900Mhz.
Seems to me that the Raspberry Pi Zero is more than capable of running most of these game consoles under emulation.
The N64 runs on <64Mhz, the PS2/PSP <300/333Mhz, and the GameCube at 500Mhz
There's a chance N64 could be emulated as well, but I doubt any emulation above 100Mhz might be a tough thing to do.
At idle, the Pi Zero seems to use around 60mA (maybe 75-100mA with a small e-ink or OLED screen).
That means the Zero should be able to run around 66 hours on standby.
At full cpu, it uses 150mA peak, maybe 200mA with a small LCD screen.
If powered by 3x AA batteries at 800mAh each, it should run about 5 hours.
Most gaming is not 100% CPU utilization, and graphics I'm talking about are between 144pix and 360pix; so GPU should not use a lot of power either; causing longer battery life than worst case scenario above!
Just thinking that the Raspberry Pi zero might be a good start for running emulators on; especially the older ones based on <8Mhz CPUs
It also fits well under a gameboy-sized case, under the D-Pad; powered by 3xAA, or perhaps powered by 2x Li-Ion generic 3,6V cellphone batteries (nowadays you can get real Samsung batteries of older phones, for almost the same price as the Chinese clone batteries), could last a good full day (24+ hours).
Would love to see a Gameboy clone based on the Pi, running (legal copies of my game) ROMS from MicroSD card.
Know any sources, or people doing similar projects?
Initially it would have been cool if the Z8080 and other chipsets would have been upgraded to todays dies, running at mere micro amps.
However, at this day and age, it may be more feasible to run everything emulated; as the current CPUs are a lot faster, and die shrinks have caused them to consume a lot less too.
Still, would love to see a system that's powerful enough to run GB/GBA/NES/SNES/GameGear games natively, and lasting a week on a battery.
Some people run the Pi Zero without HDMI and bluetooth, to save power.
if so, they could potentially run the screen from the ribbon wire connector, and use the GPIO pins for running the gaming controllers (buttons); and just need some sort of operating system and driver that will allow the Zero to be controlled with the buttons and D-pad, rather than keyboard and mouse.