Yes, the Rolex King Midas ref9630 is definitely the starter of the series and the original (please see earlier blog post for details) -- however, the ref3580 that was made for just a handful of years from 1973 onwards is very similar: same material (18K), same design, same movement, same weight, same handmade and same same -- just the dial was different, stating Cellini instead of MIDAS in Greek letters and it was not made in a limited series. But of course, most Rolex are not, instead they are limited simply by supply & price.
Well and since this reference was made just for a short period of time and it was quite expensive, it happened that this successor of the limited Midas was made in even lower quantities and is thus even rarer than the less than 800 original Midas ref9630 -- less than 500 in total and some in white gold but most in yellow gold.
See here what we have to offer currently: Rolex Midas Series