Originally posted by: Strang
Off the top of my head, I would say some Soundgarden and Alice In Chains stuff would fit that criteria for slower dirgey stuff.
Also there's the stoner rock genre which might also be up your alley. Kyuss, for example.
Originally posted by: vi_edit
Well, Black Label Society will be close. It's run by Zakk Wylde who was a guitarist for Ozzy for years.
Other bands to check out would be Corrosion of Comformity, Down(Phil from Pantera), and Fight(Rob Halford from Judas Priest).
Originally posted by: MetalMat
In fact Pantera does a cool cover of Planet Caravan.