I have never looked for an aftermarket video/USB cable for my IRD because the supplied OEM cable is high quality.
The USB is used to transfer pictures out.
People scoff at the price of the OEM cable, and it may be a bit high, but the connectors are excellent and IRD even armors the cable.
Trijicon probably makes it as well as IRD did, but I haven't seen a Trijicon contract cable.
The connector at the scope end of the cable is available commercially. The IRP uses a 9 (tiny) pin, locking Fischer connector, which is similar to a Lemo connector, that will require a very steady hand to solder and assemble.
In fact that connector is used on external battery cables I have seen sold.
But finding the three connectors (USB, video BNC, and the Fischer connector for the scope) plus suitable cable, and, importantly, making a cable right the on the FIRST TRY might just make the price of a pre-made OEM or after-market cable more reasonable than it seems, considering the consequences.