If the
GW Smaug is too expensive (who would think that!?) there is a plastic kit for the dragon from the old movie Dragonslayer. The model is still smaller than the official Smaug, but it has the same 2 legged anatomy as the movie version.
I think the human figure is listed as 1/32 scale which is quite a bit larger than a 28mm figure, and the overall model is supposed to be 6.5 inches tall. I was planning to pick one up myself as a stand in for the official miniature.