I still have not found anything dedicated of any quality, but for longer shafts I have come up with:
Greenlee 921-24 Quick Change Extension, 3/16 by 24-Inch
MAGBIT 782.18.0716QC MAG 782 7/16-Inch by 18-Inch Extension with Quick Change Shank
Milwaukee 48-28-1050 18"7/16 QUICK CHANGE ALL HEX EXTENSION
IRWIN Tools 1869518 Impact Performance Series Quick Change Extension, 1/4-Inch Shank, 18-Inch Length
It's strange that there seems to be a demand for this, but not many quality tool manufacturers are making this.