The "SUPER FACEHUGGER" (as it was dubbed) was to be introduced into the Alien Movie Mythos as the facehugger than impregnates a QUEEN fetus.
While the Super Facehugger was built and even filmed, it was eventually abandoned from the final cut. However, if you watch the extended cut (I highly recommend, btw), you get a quick glance of it... but within the context of the story, it only appears to be a regular facehugger.
Personally, I was glad it was cut from the film because I wasn't too thrilled with the "Super Facehugger" design. I felt that the design was trying hard to be this badass monster. It felt more like "The Thing" than "Alien". However, I didn't mind the Dark Horse Comics version that preceded the Alien 3 Super Facehugger....
---Just after ALIENS [the movie] debuted -and years before Alien 3 was on the horizon- DarkHorse Comics introduced the concept of a queen carrying facehugger in DARK HORSE PRESENTS #24. Their version of the "QueenHugger" looked just like a regular facehugger except with the addition of long spikes on its back. While unnecessary to have a separate creature, in my opinion, this was subtle and still worked within the previously established mythos of the creature.
You can also see those queenhuggers in the first Alien Vs Predator comic series, issue #0.---In addition, Kenner also made a "Queen Facehugger" toy in 1992/3:As you can see, it looks like it was based on the unused Alien 3 "Super Facehugger" design.
With all the above said, the Sideshow maquette looks pretty sweet. It would make a nice addition to my ALIEN Collection simply for the historical significance. I'll post more pictures later when they become available by Sideshow.