All of my stuff uses the 16-pin type, and there are 3 breakout cable versions - the short converter type, which is easiest to install with the reverse header piece, and the 40cm and 60cm versions meant to be used directly in place of the original cable:
CBL-0084L 15 cm Front control cable 16 pin split, 6" ( 15cm), (converter head), 26AWG Chassis Data
CBL-0338L 40 cm 40CM, FRONT CTRL CABLE 16 PIN SPLIT
CBL-0068L 60 cm Front ctrl cable 16 pin split, 24" ( 60cm), PBF (no converter head), 26AWG Chassis Data
The 20-pin type is:
CBL-0067 Front ctrl cable 20 pin split, 27" ( 68cm), (no converter head), 26AWG
I believe I have some extras of CBL-0084L 15 cm with converter and CBL-0338L 40 cm, probably not the 60cm version though, and probably not the 20-pin version either, but I will look around (I am planning to post a major update to my FS/FT posts soon anyway.)
The Supermicro cable matrix is a great resource as always, if slightly hokey in it's implementation:
Super Micro Computer, Inc. | Support
It lists a subcategory for a 20pin "with tube" which has no results as well as a 36pin with no actual matching cables in either.