Thea Musgrave: Soliloquy, for guitar and tape
Mario Davidovsky: Synchronisms #10, for guitar and tape
Alden Jenks: The Candle a Saint, for guitar, reader, and tape
Ronald Bruce Smith: Five Pieces for Guitar and Live Electronics, (Max/MSP)
Larry Polansky: freeHorn, (for any number of instruments and live electronics; in just intonation (or not))
Sam Adams: Tension Studies #1 and #2, for guitar, percussion, and live electronics (Max/MSP)
There're dozens more, but these are a good starting point. Of course there are also pieces for guitar and delay or pre-recorded guitars, but that's not exactly what you're looking for, methinks.