I lashed up a cable and 'pod' today. About 42cm of ribbon from an old IDE cable and 2cm of stripboard.
I measured the impedance looking into the ribbon and MSO. It is 10k at dc, down to about 2k5 at 1MHz, about 250R at 10MHz, dropping to about 60R at 70MHz then bounces up and down with standing waves above that.
I guessed at 220R followed by 91k with 6p8 in parallel as an attenuation/compensation network. The impedance of that was about 17k at 1MHz, 2k at 10MHz, and drops smoothly towards about 250R above that.
I put 4 x 5 way 0.1" headers on the 'pod' because I have loads and they are cheap for making custom adapters. 4 signals and a ground on each. The scope end stiffened with a bit of fibreglass and hot melt glue. I attach some photos and what the scope made of a 300mV 20MHz sinewave on the 'pod' (digital threshold set to 0).