There was a PSP version of Oblivion that was being made years back.

Screens and their ilk http://uesp.net/wiki/Oblivion_%28PSP%29.

There was no official reason for its cancellation. I'm guessing interference with controls (controls described seem horrid), to much repetiion, and that it wouldn't be like your average TES game.




Onto the second part of this thread, a future TES for a portable system.

I think the likely hood is better than it was. What with the new power behind the portables.
If at all, I'd guess it would be on the vita. Since it has both anolog sticks and the most console like graphics.
This would probably also move a good amount of systems. I'd buy a vita if I could play TES while on break at work.

Though I wouldn't want it if it detracted from the next "main" TES game.

Here are discussions about the cancelled PSP game.
http://www.gamesas.com/topic/901784-elder-scrolls-travels-oblivion-psp-not-cancelled/