Unless you have a double-cutaway'd Acoustic guitar with easy access to at least 22 frets (doubt it), you will have to resort to using an electric guitar. Realize that the sounds are dramatically different, and if you want an accurate representation of Stairway to Heaven, you will have to adapt your gear to fit the song. That, or play the entire song with an electric guitar; Half the people in the audience won't know the difference, and realize that Jimmy switched guitars about 4 times during the song; my advice would have to be to just play the song on the electric guitar, much more versatile, especially for a song such as STH.

~Incidents