Just as a note, though I haven't played it, there is a new Iron Kingdoms RPG by Privateer Press. And its Combat is based on their Warmachine/Hordes Tabletop Miniature Wargame. Maybe sth for you?
I really like the IKRPG. I'm playing in a game of it. This grid based fantasy game is for a different group that doesn't really like the steam powered thing or the emphasis on firearms and robots. I may end up using it as the basis for this project and just excise the Warmachine specific stuff.