Alden Lee

Maker of fine hardwood furniture for early musicians, including music stands, instrument stands, players' seating, and others. 
Location:  Menlo Park, California.

Clarion Associates

The largest insurance firm dedicated solely to the needs of musicians worldwide. 
Location:  Huntington Station, New York.

Musicmakers Kits

Makes and sells kits for making all manner of early instruments. 
Location:  Stillwater, Minnesota.