This is new to me but Bessey has released an inexpensive adapter dog kit that's designed to allow their self-adjusting toggle clamps to be retrofitted so they can be held stationary in 20mm holes with the base resting directly on the surface of the table (rather than requiring an additional elevated DIY or aftermarket base plate):
From Bessey:
http://www.bessey.de/pdfs/press_releases/BESSEY-Tool-Novelty-Accessory-set-for-toggle-clamps-on-multifunctional-tables-STC-SET-T20.pdf
A short video showing the Bessey MFT clamp adapter in action:
They also released complete clamp/dog kits (that include the adapter w/a clamp):
https://www.its.co.uk/pd/STC70-SET-MFT-Bessey-Toggle-Clamp-For-Festool-MFT-x-2-_BESSTCHH70T20PK2.htm
In addition, they are also producing an inexpensive adapter that allows their existing range of clamping elements to be modified for use in 20mm holes:
From Bessey:
http://www.bessey.de/pdfs/press_releases/BESSEY-Tool-Novelty-Clamping-elements-for-workbenches-TWV-TW-TW16AW.pdf
And, from Bessey North America [Note: this is the version for 16mm holes]:
https://www.besseytools.com/en/product_details.php?ASIMOID=000000030003bea300040023&ASIMOID_SC=000000030003cd8400040023&ASIMOID_MC=000000000001f3f000030023
Pretty neat!

From Bessey:
http://www.bessey.de/pdfs/press_releases/BESSEY-Tool-Novelty-Accessory-set-for-toggle-clamps-on-multifunctional-tables-STC-SET-T20.pdf
A short video showing the Bessey MFT clamp adapter in action:
They also released complete clamp/dog kits (that include the adapter w/a clamp):
https://www.its.co.uk/pd/STC70-SET-MFT-Bessey-Toggle-Clamp-For-Festool-MFT-x-2-_BESSTCHH70T20PK2.htm
In addition, they are also producing an inexpensive adapter that allows their existing range of clamping elements to be modified for use in 20mm holes:


From Bessey:
http://www.bessey.de/pdfs/press_releases/BESSEY-Tool-Novelty-Clamping-elements-for-workbenches-TWV-TW-TW16AW.pdf
And, from Bessey North America [Note: this is the version for 16mm holes]:
https://www.besseytools.com/en/product_details.php?ASIMOID=000000030003bea300040023&ASIMOID_SC=000000030003cd8400040023&ASIMOID_MC=000000000001f3f000030023
Pretty neat!