is it possible to build a cmoy that runs off AA's or power outlet?
To make a cmoy (or any amp for that matter) that runs off AA or AAA batteries, you can simply make a battery pack with sufficient batteries to reach the desired voltage and then hook it up to the amp somehow.
To make any amp wall powered, you'll have to make a power supply to bring that mains voltage down (amongst other things). There was a thread recently on this topic i believe, you should search the DIY forum for that.
and have a switch that acts like a ER4p-er4s converter?
Although ive never done it, im sure you can easily make an adapter switch with a switch and a few resistors (you can search the forums, there are probably people who've done it).