This model screams an early Rogue Trader aesthetic to me - but remember that Rogue Trooper was first! It demonstrates how much of the early 40k was inspired by sources such as 2000AD, Judge Dredd, etc.
It was difficult to find a source shot for the Souther. I searched online and found some in black armour, others in green (this seems to be a newer scheme), and eventually went with black (mimicking the Mongoose website version).
Here's a group shot:
I'd definitely be interested in purchasing more of these models, but sadly the Mongoose Kickstarter seems to have stalled. It ran in 2013, and did quite well (although not as well as the JDMG Kickstarter). However, I've read online that Mongoose had a problem with finding a sculptor for the project - the upshot is that it has gone into storage, and since the release of these models there haven't been any new Rogue miniatures. That's a real shame!