We've just released the "Gundogs" for our alien Soriog Empire range in 15mm.
These are large robots with four legs, built around the Hex Cannon energy weapon, which follow the Soriog and Raug around on the battlefield providing heavy close-fire support. They're almost like light tanks, so large are they in 15mm scale -- in fact 28mm gamers can definitely use them as sentry or fire support bots as well. Toward that end we have prepared some comparison photos. The first one shows them compared to a 15mm Raug Ceepay:
... and the second one compared to a 28mm Federal Army rifleman:
Available now: http://khurasanminiatures.tripod.com/15mmscifi.html