Well, after much research, I believe it must be Scaglietti.
That's what I was looking for, yes!
Although the info out there says Scaglietti was the designer rather than the builder I'm not 100% sure I believe that.
Scaglietti were first and foremost craftsmen who built many Ferrari racing cars, but whether they actually 'designed' them rather than just crafting functional (albeit very beautiful) bodies I'm not so sure. And would Scaglietti really have designed a car for someone else to build? I don't really think so.