I have made one nice shadow test.Give it a look:
Tnk, there is actually a way to get high detailed shadows in goldsource. This is what my map looked like before i ported it to sourcePICTUREFINGYLOLZ
I'm not sure what method you used, but those shadows look razor sharp/hard.
Basically, the lower you scale a texture, the more lightmap quality you trick the engine into drawing; so a surface with a scale of 0.25 can have about four times more detailed lighting than a surface with a scale of 1.
But in order to do that without screwing up the appearance of a texture, you need to export the image somehow, stretch it to as high as possible, re-import it with wally then apply it to a surface in game and lower the size (so it will look normal as well since you stretched it for this purpose) and you should then get a surface with high lightmap detail, so then the engine can calculate its own shadows rather than have to improvise with artificial ones.