These seem to have been popular. I've done some more - with mixed results.
Particularly pleased with the Claws of Axos - done using alternative photo references to the ones on Chris Achilleos' original.
Also the one from Inferno. I've never really liked the finshed original cover - the figure work looks a bit off to me but I do like the imagery.
The Three Doctors offers a 'different' take on Omega's hands.
As for The Dalek Invasion of the Earth... I'm not sure I should've even started that one now. I went a bit TOO pop art with it...