Not IHMN, but I am working on a 15/18mm VSF project using Black Hat Miniatures Martian Empire, Blue Moon Victorians and Highlander Studios Martians.
If you don’t have any already, I highly recommend the Blue Moon figures for Victorian civilians. They are beautiful sculpts. I’m going on leave next week, so will put up a few painted examples on my blog, because I struggled to find any painted examples online.
Those are brave men knocking at our door. Let's go kill them!
I would love to do a Martian Empires setting. I think the Martians from Black Hat are wonderful, I have not seen the Highland Studios ones yet.
For the humans there are many options, any colonial figures really. As for armour and the like All Quiet on the Martian Front will offer some ideas as does Spartan Games Dystopian Legions, I know they are 28mm but some of the vehicles would make very good large vehicles.