Philip Glass: Piece in Shape of a Square (alto saxo and CD, or 2 alto saxos), Melodies for Saxophone (unaccompanied)
Graham Fitkin: Hard Fairy (soprano saxo and 2 pianos), Gate (soprano saxo and piano), Glass (soprano saxo and piano), Pam & Jim & Jim & Pam (unaccompanied I think)
Jacob ter Veldhuis: Billie (alto saxo and CD), Garden of Love (soprano saxo and CD), and Grab It! (tenor saxo and CD)
Michael Nyman: Shaping the Curve (soprano saxo and piano)
Steve Reich: Reed Phase (soprano saxo & CD), Dorian Reeds (any saxo w/ delay)
Gavin Bryars: The Green Ray (soprano saxo and piano)
If you're up for some easy arranging, Spiegel im Spiegel (orig violin/piano) by Arvo Part is beautiful for soprano or alto and piano, and pretty much any piece from Michael Nyman's vast output of film music works as a nice simple interlude.
I would describe all of these suggestions as good minimalist solo literature. The times that I have paid to attend concerts or buy CDs of this music, I have always enjoyed.