>>92640930>>92640909He has done hardcore work: Both for commissions and private reasons. He flat out admits it in one of his mid '00 comic con interviews.
The commissions are both insanely expensive and require almost Illuminati level connections to get. (and require one hell of a NDA because he is deathly afraid of anything getting out.)
As others have mentioned, it will be up to the family and whoever owns the rights on his commissions to release them once he passes.