Ahem, now back to my original question... any suggestions on suitable cable? Yes, thanks, I've seen that vendor and I am trying to avoid buying a roll of the stuff. I haven't found it in smaller chunks yet.
I am considering building my next Kelvin cable with RG316/U cable.
Isolation made of PTFE, good shielding, inner core made of silver plated copper.
Edit: and it is flexible.
But I'm not really sure, if this is a really good idea. Must test it.
Flexible? Sort of.
One other possibility would be to use the shielded single or TP of MIL-W-22759*, i.e. Raychem Spec55 or similar. Slightly more flexible, with somewhat less screening at RF.
If someone comes across Spec99, that would be REALLY flexible.
There was a description in Wireless World, IIRC, on the construction of such test leads which involved using a gutted RG58 as outer screen and sheath.
Concerning flexibility: RG316 is still far away from the stuff the probe manufacturers use. Does anyone have a commercial contact for that? (Surplus or such. I know well who would supply that new, 1000m-wise)
*: watch the slash sheet. Not all of them are flexible enough. Must be one of the thin-walled, finely stranded variants.