Since about 2011 I've started using dvorak as my main keyboard layout and like the efficiency compared to QWERTY.

Dvorak in dos

To use dvorak in dos download this file containing dvorak.com
Transfer it to your C:\DOS folder for example and add this to your AUTOEXEC.bat: 

C:\DOS\DVORAK.COM
When your computer boots the program will say DVORAK is loaded and you're good to go

Dvorak in dosbox

Dvorak is also usable in dosbox via a custom mapper file that your can find here
You can enable the layout by saving this in your settings directory and 

mapperfile=dvorak-0.74.map
to your sdl section of your dosbox config.