Tyreon,
There's a KORE i-Beam mono- to twinrail adapter currently available from a shop in Malaysia here:
https://www.rodalink.com/my/catalog/product/view/id/11565/s/kore-rail-adapter-for-seat-postListed cost converts to a pretty reasonable price, so even if shipping were pretty steep it might be worth it. If delivery is only available locally, then perhaps a store in Puchong, Selangor (where Rodalink is located) might reship to you for a fee. I've found M'sian shops to be very accommodating of my distant ordering needs. A Google search shows these adapters are more common in Asia; I saw one available in Singapore on their version of Gumtree/Craigslist.
I have learned some new-in box Kore i-Beam seatposts included the adapter as well as the post for T-rail saddles, so it might be worth looking to see if you can find one of these on eBay. Last I saw, they were going for about USD$15, in the UK for about £20. Have you written Kore or the "D" or "T" brand maker of your bike? Either or both might have the adapters available. Looking at how the saddles sit and where you have a Folder, it appears to me a railed saddle on an adapter will stand more proud of the seat collar than the i-Beam/T-rail combo, so your folded size may be larger than original once you convert to a conventional railed saddle.
The piece doesn't look that difficult to reproduce...it needn't be as complicated as the KORE adapter. All you really need is an adapter shaped like this in end view:
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The vertical "fins" tying to the KORE mounting bolts in the "official" adapter appear to be for convenience in fitting rather than necessity. I really don't think you'd even need a machinist to make one...just a drill press and a chunk of aluminum. I'd take a 12.5mm/1/2in thick piece of aluminum and drill two 7mm/9/32in holes of the proper spacing through it vertically, then split it halfway through the holes' diameter and call it good. All you'd need to do is slide this "adapter" between the saddle rails and then affix the KORE side plates and...done. Looked at this way, you may have more flexibility in manufacturing options, as John suggests.
Best,
Dan.