This was a big surprise: apparently in the UK they made Sammy Steel variants. Information about the toy line itself is already pretty damned obscure, so to find out that there were variants is pretty incredible. These photos are courtesy of an ebay user who will hopefully confirm whether these are authentic or reproductions.
Compare to the original parts below:
Spaceman figure is in this pic. ^
The paint on the originals and the variants are both equally cheapo. The sticker placement could be achieved if the set was re-molded at home, and the outer casing appears to be molded from black plastic and not simply repainted. If anyone has photos of more variants, do send them my way so I can confirm if this is the real deal or not.
UPDATE 1/6/2016: Holy crap, they’re real. Someone else has been selling them, too! I stumbled upon her Dome of Doom variant below:
And when I asked her about the item, she kindly linked me to a previous sale, a Sinister Saucer variant!
The US version:
This is amazing to me. That this obscure-as-all-hell knockoff toy had regional variants. If anyone has a complete set, send me all your photos and ebay listings!
UPDATE 3/18/2016: Found something even more mind-blowing, courtesy of a very difficult-to-find UK ebay listing.

My first thoughts were along the lines of UK Sammy Steel being distributed under a different name, but upon closer inspection, Imperial’s brand name is entirely absent from the packaging. This leads me to believe that we are looking at a BOOTLEG of a knockoff of Mighty Max.
I tried to convince the seller to ship to the US, but they’ve been unresponsive, so it’s likely I’ll never get my hands on this one.
UPDATE 5/15/2020: Got a carded knockoff, so it seems they’re not just UK variants. Someone took the molds and made alternate playsets minus Sammy. Here’s a Dome of Doom comparison.
I like the idea of one playset for the bad guys and one for the good guys.