Why would you need a pump like that? Most mineral oil cooled PC's use normal watercooling pumps since mineral oil is close to the same viscosity as water. A fairly normal watercooling pump would likely work. However, you run the risk of o-rings on fittings or inside the pump failing due to the mineral oil breaking them down.
My next question is...why do you want to use mineral oil? It will basically ruin all the components since the oil will saturate the PCB of the motherboard, cards, etc. People have done this, but it really isn't much more than novelty and 'to say you did it'. Good luck.
This probably should've been posted in the watercooling forum; you would have had more responses. Again, some people have done this, but there are other alternatives to submerged oil cooling, unless you are dead set on the concept.