I took Vezkah's Printrbot Simple Metal Spool Holder 2.0 and resized the hole so it fit on the original Simple. Works great on my Printrbot Simple 2014!
The full size is too big to print on the Simple 2014 itself, but I've included a scaled down version that will fit the 2014 - however I'm not sure if all spools will clear the printer on this smaller version - let me know if it works for you!

Be careful with very high prints, I managed to dislodge the string on the Y-axis of my simple because it was rubbing against the spool holder.

Print at 25% > infill and slide it on one of the z-axis posts!
To get the "small" version to print on the Printrbot Simple 2014/ Makers edition, you will need to rotate it 45 degrees on the Z axis (IE: put 45 in the Z box on the rotation line in Object Placement)