Has anyone made or know how to change the shields, so that they look like Goa'uld shields ?
As I understand you can only have one shield for all the ship types so you would end up with goa'uld style shields on other races ships (like the asgard) where they don't belong.
But to answer the question, no I don't know.
I would use the orange asgard type 4 all ships, as they are the closest in the middle.
The effect that apears on the shield when hit can be changed in a texture file (xshldie.tga or something similar I don't remember exactly) but only certain mods know how to change the color of shields and they are keeping it to themselves until the mods are released I believe. The effects can be changed though I think a nice crackling effect would be good.
Without looking I would imagine its a case of changing the shield SOD or sprite.