Here's an idea: run the emulator/games in the PC and stream to the iPAD

[Perene]

There's a free app for iOS called Microsoft Remote Desktop.

The link for the download and additional details can be read here:
http://microsoftremotedesktop.wiki-site.com/index.php/Microsoft_Remote_Desktop

Running the emulators from the PC I can stream them to my iPAD. They look like this, for the SUPPORTED ones:

Which are PS1, PS2, GameCube/Wii and a few more.

When an emulator is only partially supported it looks that way in the iPAD:

After I apply zoom, it may look like this:

In these pictures you are seeing nullDC, which runs in fullscreen mode, and DEMUL, the only emulator I used so far that didn't crash Resident Evil 2.

And then we have a third scenario: the emulator doesn't run at all and gives me a "unable to set display mode", direct3D error, etc.

This is what happens with MAME, and I believe SSF (Saturn). However I have seen happening with PC games as well. The DEVIL MAY CRY 4 demo (one that I tested) can only run in window mode. But Pro Evolution Soccer 5 (another PC game, this time released in 2006) doesn't work at all.

Two GameCube games:

The question I really need to ask: why this app cannot stream every single game that is running from my PC? Why can't I have ALL OF THEM listed in "SUPPORTED"?

P.S. The higan emulator can run Game Gear, PC Engine and Master System in fullscreen, yet there's no sound in the PC, that's why I have not listed yet. And this emulator (at least here) is not recognizing any Genesis game.

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Updates:
M.A.M.E. and Nintendo DS working, check the wiki for more details. 3DO, too.

Edited February 27, 2017 by Perene