Piano Lane (
There is a section of sacred music, and it can be organized by solos or duets.

Marshall Music (
There is no online catalog, but you can place orders if you know what you want.  Store locations in Grand Rapids, Lansing, Kalamazoo, and more.  They sell music for all instruments.

J.W. Pepper (
You can search by instrument and they have an online catalog for sacred music.

Creative Ministry Solutions (
Provides quality puppets and supplies for Christian puppet ministry, blacklight, children’s music, gospel magic, clowning, ballooning, etc. (
Download sheet music.  Includes a section for Christian music.