I could never see rechambering a perfectly good .357 cylinder to this wildcat, until 'convertible' was mentioned. Duh! I have a .357/9mm convertible, and the 9mm cylinder doesn't see much use. Now it makes sense.
The Hodgdon/Shooting Times "Hodgdon's Annual Reloading Manual" has .357/44 B&D load data, for the princely sum of $7.99 (suggested retail).
Looking at the data, though, not sure if there is a lot of gain in a handgun. Comparing to the .357, both with a 10" barrel, both loaded with H110 and Hornady 158gr. JHP, the B&D gains a whopping 13fps while using 4.3 more grains of H110. The pressure of the B&D round isn't listed, though, and it would appear from the data that it is held much lower than the 40,000CUP of the .357 mag loads. Probably they kept it low to avoid problems with setback.
In a rifle, though, or Contender, setback would not be the issue and you ought to gain a lot more.
Interesting, and if I could come up with a reamer cheap, I'd certainly be tempted. I think that you could use the chamber reamer to make a sizing die pretty easily.
