They're a very common and well known tool. I would think any major supplier, such as Ellwood Epps or Cabelos would have them.
As an aside, be ready for quite a bit of fun to start with in adusting the die, so the lubricant ends up only in the grooves, and not all the wrong places!
Don't hesitate to ask questions on here, as a lot of people are/have been using that equipment.