Maybe this is useful for you:
http://www.pgdp.net/wiki/Accessibility_Recipes/Dropcaps
But the code may not work so well in ePub readers, and the amount to move the text changes from letter to letter (and font to font!).
I wonder if it's better to have duplicated code toggled through media types (assuming this is supported by ePub readers and text-to-speech software).