If anyone is interested in the calibers, Lee and his father developed those and do all the work putting the revolvers together. As noted above, they also make the dies for handloading their ammunition.
You can see an example of their work in the "sticky" in the Revolver section of this site about the 44 Special conversion of an old model Ruger 357.
You can also go to Lee's website at http://www.singleactions.com and read about all the calibers this dynamic duo has created over the years.