If You do a search with the keywords Neuser and NFS, you'll have your hands full of threads.
Bound to be on one of them.
With a quick skimming through those threads, I was able to find this reply from pilotjones
Originally Posted by pilotjones
I had thought about doing something, which may be what the Neuser NFS does.
[ begin informed but unproven analysis ]
With a fretless, the "mwah" sound is produced by the string "scrubbing" (actually scrubbing with respect to side-to-side motion, and bouncing with respect to up-and-down motion) slightly against the fingerboard just ahead of where you press it down. That is why action height affects the mwah - as you raise the action, there is less scrub, and less mwah. Also why plucking harder mwahs more - more string deflection, and more scrubbing.
What is happening is that the string is trying to deflect into an area where the fingerboard is, and it "bounces" off the fingerboard. The harmonics generated are higher overtones because of the short distance from the scrub area to the node. And the mwah "blossoms" on some basses because energy from the fundamental is being converted to energy of higher overtones.
[ end analysis ]
Anyway, imagine that there was an area at the bridge node that resembled the fingerboard node on a fretless. To create this, you could just lay the string over a hard surface at the bridge, and adjust the angle for proper sound. There is no reason the surface would have to be under the string; the conventional saddle could stay under it, with the surface introduced from the top. And that's what I am guessing Neuser is doing.
That's not the thread I remember seeing, but should give You an idea how it works.
I was also able to find some AllParts prices from -05, $285-> for 4 strings and $345-> 5ers.
There's plenty of comments, for and against, there as well