Bowen or any of the custom Ruger smiths wiuld be happy to oblige. However, IIRC, as with a .327 conversion, with the new cylinder it would require "adjustment" of the B/C gap, at a minimum, and unlike the .327 also IIRC maybe even require opening up the cylinder frame window, thus rendering the .32 H&R cylinder either defunct or at the least less desirable-- if you're thinking convertible. With a .327 conversion it's not an issue. Although the .32 H&R cylinder is, in effect, discarded in the process (you see a lot of H&R cylinders for sale out there), .32 H&R can be shot through the .327 cylinder.
Edit: I'm sure not the idea you had in mind, but a larger custom (.32-20 length) .32 H&R cylinder could also be made "to match" but then you"re talking increased bullet "jump," not to mention significantly increasing project budget.