Since there is notation software today on Windows, and such runs on Windows 8 Pro tablets, why did you lead with or seem to claim there was no such thing?
There already are a plethora of tablets that could in theory be used on a music stand. However the music publishing industry has not yet caught on to the real potential here.
I play classical guitar and my ideal would be a letter sized or ten inch tablet or e-ink device that could be page turned with a foot pedal device. I easily edit all the lessons and music that I create in PDF already. And this music is polyphonic and quite complex. Much more complex than simple melody lines.
How many musicians are out there that use music notation set to PDF already? I suspect many do.
Would it not be a very reasonable idea for publishers to finally get out of the paper publication and distribution of sheet music once and for all? Seeing that paper music publication is suffering the same fate as the recording industry as music stores can no longer afford to stock it. Thus it is very hard for publishers to keep great classical music in print especially for instruments like the classical guitar.
The only sensible answer is to completely change the distribution of sheet music to digital the same as what is needed for the great classical music recordings. DGG has already made the jump to online sales of flac, aac and mp3 audio for this very reason.
We are in a temporary classical music dark age where even in the major cities it is difficult if not impossible to easily obtain either great sheet music or great classical music recordings in shops. Sony just sits on many of the great recordings, for instance it is almost impossible to obtain the great recordings made by Igor Stravinsky on Columbia.
Same thing with the great music publishing houses like Schott publications, Universal, Berben, Peters, etc they are a but shadow of what they once were.
This situation must change and soon or only the extremely wealthy will ever have access to what is at the heart and soul of western culture!
Think of it this way once upon a time Mozart was the king of pop top 40 of the 1790's, as were the melodies of many other greats like Puccini, Verdi, Downland and the list is endless.
We are strangling our culture and the music industry must change and soon, hopefully before I pass from this existence.