Here is an idea with a difference and very easy to make.
Use ca 3mm silk braid and tie a Chinese button knot with a loop of about 2". Finish the ends either close to the button knot of leave them longer for effect.
In use, pass the loop through the shirt buttonholes to the outside of the cuff, then pass the button knot through the loop sticking out the outside of the shirt cuff, gently draw the loop slack back to the shirt cuff retaining the button knot against the cuff.
Easy to make, easy to use, very effective, and I bet you will not see the like anywhere else.
Derek
Just out of interest, Derek, and assuming I understand your description correctly, I did find a PDF somewhere on the Internet entitled summat like "Ye Compleat Guide to Cufflinks" and there was mention of such a thing in metal.
It is referred to as a stirrup cufflink, and, according to the august authority that produced said document, "is considered gaudy".
I cannot imagine a knotted one such as you described being gaudy (unless you used my hot pink pseudo-spectra
) so maybe there is a whole new market opening out there for the Brotherhood of Sore Fingers to exploit. Businessmen the word over free at last to wear stirrup cufflinks without fear of being shunned in gentlemen's clubs ...