Hitachi makes the cable:
https://www.hca.hitachi-cable.com/products/hca/products/ribbon/wide-pitch/0.100-pvc-stranded-wide-pitch-ribbon-cable.php

I have yet to find anybody that makes the IDC plugs for 0.1" pitch without buying them a thousand at a time. Widest I have found available is about 20 pins wide so you will probably need to use connectors end to end - so make sure they are sized for end to end clearance.

I have 350mm (just under 14") versions of these cables. The manufacturer for my cables will make these any length you want but you need to buy 500 at a time.

They're not open-able without destroying the latching mechanism.

Made by Don Connex:
http://www.donnex.com.tw/EN/products-list/nodeA/1394878204000/nodeB/1395899384000/

They list an "A50" version which is advertised as 32 pin widths. Unfortunately they no longer make these and several other styles on that web page but won't take them off the website.
Seems the only one they have readily available is the A04a.

Maybe they'll send you a few sample plugs along with a couple feet of L04C cable...?