Yes, of course they do. The original manufacturer open-sourced the design years ago, was a guy over on Amibay making knock-offs right up until recently, maybe he even still is. He made copies of the original Thylacine (with one USB port) and also a "Mini Thylacine", which had two ports, or four, I think it was four running off a header... don't remember off-hand but there was tons of pictures posted in the threads on Amibay.
As far as "how did they work"? Well, I had one of his Thylacines, and it *sucked* in my A2000. Would completely bog the system down as soon as you plugged in any device. Spoke with one other A2000 user who had the same problem. But this was a Zorro-II issue not a Thylacine issue. I sold mine on and traded up to an X-Surf 100 with RapidRoad module, and couldn't be happier with that combo. Something about how the RR handles devices that the much older Thylacine couldn't, blah blah, TL;DR. Thylacine works fine if you have an A3000/A4000, but RR or Deneb or other options are better. 
It is not the Thylacine that uses the resources, but the USB stack (Poseidon); the original designers own software ran without a noticible speed hit. The Poseidon software can be used along with a small script to turn on the stack, reset some priorities, and when done, shut down the stack releasing those priorities. Poseidon REALLY loves an accelerated system.
The original Thylacine is slow and needs a powered hub, but the 4-port mini Thylacine improves both aspects.
