I came across this bust on the JMD miniatures website. They make some of the nicest models ive come across and the moudling is superb, very little cleaning up required.
He was painted using a combination of vallejo, citadel and newly for me, some Formula P3 paints. These are made by Privateer Press, and i have to say, ive been very impressed with them. Unusually for the fantasy miniature world, they dont just ape the GW colour range, and their whites in particular are very nice to work with. In general the paints are more opaque than the vallejo or citadel ranges (the closest is probably the citadel foundation range). The thin extremely well, even with just water and the whites dont become chalky. I would highly recommend trying them out, especially Menoth white base and highlight and Sanguine base.
With Subject X1 I was trying to achieve the look of something that was, at one stage, human, but the experiments that have been performed on him have changed him inside and out! I also wanted to give the impression that he was a test subject, hence the shaved head and barcode on the back of his neck.
Hope you like him!