Unfortunately it is not possible to use CTRL or ALT, however Keyboard Mappings ARE case sensitive- so you can use Shift (or Caps Lock) to nearly double your available letters. Punctuation characters are also able to be used, so you can access these with Shift too.
Hmm, that would be something that would likely need to be handled on the side of the operating system, or perhaps through some 3rd party application (if any such application exists- I can not say for certain).