[pz]

is there a standard mapping for chorded keyboards? i feel like X has a much easier combo than E. would be interesting to use data on people's error rate for different key combos and then remap frequently used letters to easier combos.

[gnosis]

The only standards I'm aware of are standards for stenotype machines (chorded keyboards that stenographers) use:

https://secure.wikimedia.org/wikipedia/en/wiki/Stenotype

And there are a fair number of competing standards and keyboard layouts (especially if you count layouts/standards for various languages).

Stenotypes machines and musical instruments are really the only chorded keyboards in wide enough use to develop any kind of standard.