So I've been thinking a lot about the possibility that the secret is only visible on a large scale - perhaps on the scale of the entire rift itself. I've scanned around looking for anything peculiar in the map, filtering star types here and there to see if anything interesting appears. I've found no smoking gun, unfortunately, but there is at least something of interest - brown dwarfs. T and Y class dwarfs are ludicrously abundant in a thin plane just a few dozen lightyears beneath the y = 0 plane throughout the majority of the galaxy. I've placed a link to some images of this plane, viewed edge on in the rift, below. I've included a view of the main sequence stars surrounding the plane sans the dwarfs, creating a gap, and the dwarfs themselves.
http://imgur.com/a/g30VS
Now, this on its own is nothing special. As I mentioned, this plane is present all throughout the galaxy. What is more interesting are occasional gaps in the plane - gaping holes where no brown dwarfs exist. Now, while that sounds tantalizing on its own, it's important to note that I saw some similar gaps pop up in other regions of the plane, not in the rift. There's a good chance this is just a quirk in the generation system. However, the gap in the Formidine rift, particularly on the Heart & Soul side of the RR line, is exceptional. As you move out from H&S through this dwarf plane towards the outer arm, it will display more and more gaps until the plane seems to disappear entirely, re-appearing once closer to the outer arm. Now, the sporadic gaps are not necessarily that important. As I said, occasional blocky gaps (more "natural" gaps that don't have such sheer cutoffs would be intriguing) is nothing new as far as I can tell and are only quirks of the engine. But inside the huge gap (which itself is probably a result of the general low body density of the rift, and is NOT a procedural quirk. Too big for that.) is the occasional cluster of brown dwarfs, just hanging at the same level that the plane would usually be found.
Remember that Drew said he considered dark systems to include brown dwarfs and other un-scoopable bodies - perhaps these islands of brown dwarfs in the massive gaps would be interesting to investigate. They would certainly serve as an excellent hiding spot, as most CMDRs steer clear of the unscoopables as much as possible - diving into a field of them could well turn out to be suicidal if extreme care is not taken. If one does not wish to go all in, simply looking at where the smaller clusters pop up in the gaps and noting their locations might yield a pattern. Hell, if we're thinking on a more technical level, they could mean nothing in terms of plot but rather coincide with small areas with higher star density - just find an island, then turn on the visibility of main sequence stars and move back upwards or downwards out of the brown dwarf plane and perhaps there'd be more in that region then above or below a blank spot in the dwarf plane. If this is the case, I suppose it's a bit gamey as it's trying to read into the workings of the engine, but it might be helpful to those having difficulty plotting their way through tough spots. Whatever the case, I can't help but think that a field of brown dwarfs would be a natural choice to hide things in if I were in charge given the dangers of navigating them. Perhaps they shouldn't be neglected.
.