Try a Porceline slide, nice even tone. It isn't a fragile as glass, but sounds fuller than chrome. Dunlop makes a bunch of models. For Lap Steel, I use a neat Shubb Bar that is steel but with a Rosewood grip, feels and handles awesome.
Perhaps dropping the Pick could help too. Lots of slide players go bare fingered and the tone is MUCH fuller. Also, you can use the other right hand fingers to mute any strings you're not using. Ben Harper comes to mind, he has a MONSTER tone.