What res DEM have you got then ? I reckon the SRTM3 at 3 arc second is about the highest I can get. 3 arc sec is about 100m or so per sample.

Another interesting way to get higher apparent res than what you have is to get a normal map of the DEM and lay that on top of the lower res mesh. Still, if res is not what is holding you up then this is not so good. Mention it if this would help tho.