I have some idea, being impressed by arensito keyboard layout. It is possible to create a layout with all necessary keys on three central rows. Some keys will be "modifiers", such as shift, alt, etc. in qwerty. But it is possible to create more such keys. E.g. one modifier-key for punctuation, one for numbers, one for control-keys (arrows, pgup, pgdn, home, end, ...). One hand is pressing modifier, and other have a half of keyboard to press modified key.
It is necessary to investigate frequency of key-presses not only for ABC, but also numbers, arrows, ... .
I know, this layout will be extremely difficult to learn, but it will be possible not to move hands above keyboard.
I don't know, if it is possible to create such layout on Windows (simply).
I don't like arensito - it uses 4 rows and it isn't extensible enough to work with other alphabets, such as cyrillic. And afaik it doesn't work on Windows.
P.S. Colemak is gj. Dvorak's "l" and "s" tire me...