I think maybe what you want is a different keyboard layout, not a new font?
There are a couple of programs you can download which allow you to input Greek text using betacode (I use Tavultesoft Keyman, but there are a couple of others). Or you can create a custom keyboard to replace the standard polytonic one. In both cases you will still need to change the setting on the language bar when you want to switch from Greek to English, but this is surely not more difficult than switching the font setting?
You might try one of these sites: (I think there's another free app which doesn't use Keyman but I can't find it right now.)http://freenet-homepage.de/LukasPietsch ... oards.htmlhttp://scholarsfonts.net/keybrds.html
If you're a mac user look into SophoKeys.
I would recommend using this method rather than a special Greek font like SPIonic, since texts typed in (eg) SPIonic look like gibberish in any font except
SPIonic. If you use unicode input (as with the polytonic keyboard), the Greek characters will always display properly, providing the font you're using has unicode support.