"Empress Minis gasmask heads on LAM bodies - - "
I don't own a lot of Empress Minis but the LAM figs are chunkier and larger than the handful I do have. The EM figs are nice, don't get me wrong, but the Pig Iron Productions spare heads seem a better fit for LAM.
That said, I think EM heads would work with Eureka figs or Spectre. Or perhaps The Assault Group as well.
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Look into the Tiny Terrain Chechen War range. Igor K's sculpts but smaller than LAM. That might be a good fit too.