We have just released something for 6mm sci fi gamers that 15mm gamers will love too! These are our Federal Navy Neptune Special Forces mechs in 6mm, but they are exactly as tall as a 15mm sci fi infantryman, so they would also make excellent war robots in that scale. There are two in a pack and they come with separate arms for more multiposability.
Available now:
http://khurasanminiatures.tripod.com/6mmscifi.html