i posted this earlier:
http://www.sevenstring.org/forum/rec...-e-tuning.html
it´s a song i made with my 28" baritone, tuned to the Sikth-tuning (the lowest string down to an octave below the string after it, you know the deal), but tuned all the way down to E. this is with a .65 for the low E, and it works pretty well. it´s loose, but useable, i even recorded a whole song in drop E tuning, where all the strings are tuned down as well.
if your guitar is 28" or more, you can go down to E without issues. this thing handles F# and F easy. E would be perfect with thicker strings too
so if your guitar is 27" or more, f# shouldn´t be much of a problem, though i wouldn´t get anything less than 28" myself, but i´m a baritone geek :P