You can modify bitmap fonts to have more than just outline and shadow effects. You can add a slight bevel, glow, or even add a border around characters so that you can then modify them in Photoshop to add any effect you like. Create a bitmap font then select the font prefab to see the built-in options.
Dynamic fonts are too limiting and this won't be possible. Also note that in order to draw an outline effect without modifying the font's texture you need to draw the text 5 times. That's a lot of extra geometry. Shadow -- draw it twice (once for shadow and once for the foreground). So shadow + outline would be drawing the text 6 times. Bitmap font modification approach involves drawing the text only once. Far more efficient.
