Have you ever tried using vocal harmony technology? If not, I strongly suggest that you do.
I have a Digitech Vocalist Live-4 that I use at every gig. I love it!
You plug your mic and your guitar into the 'box' and then take one-output to the board. The 'box' analyzes both the chords you're playing and the notes your singing to create perfect vocal harmonies.
There is a wide variety of harmonies that can easily be selected via the foot switches. As many as four-harmony voices can be selected.
The 'box' also has a large number of effect options for your guitar.
When performing as a solo-act, I find that the vocal harmonizer gives me that 'little something' that enables me to change-up my sound throughout the performance. Keeping the audience engaged and interested is very important and this tool does the trick.