While there are a couple of laboratories in the U.S. that plastinate human body parts, the largest manufacturer is in China. In the U.S. bodies usually come from donors. They may have been previously used, in part or in whole, for other projects such as schooling or human tolerance testing. China also has body donors. But, they have been well publicized as using the bodies of executed prisoners. (They execute a lot of prisoners) I think Fisher Scientific uses American plastinated parts because the foreign parts are rather difficult to bring through customs.
I'd like to see the day when people finally get over all of their superstitions regarding the dead and their disposal. Wouldn't it be nice to be able to plastinate a friend or loved one (preferably departed) just to keep them around a bit longer? Wouldn't the ex-spouse make a fine lawn ornament to place under a tree where pigeons roost?