I'm interested in moving the four gadget namespaces to a shared read-only wiki. I want to refer to those namespaces via interwiki prefixes, mapped to the URL of a wiki that holds these content pages. To edit any page retrieved from a remote wiki, a user would need to login to that wiki to perform the editing.

Happily, I am able to create a multilingual semform by a) using {{UILANGCODE}} in switches and b) using the 'mapping template' parameter on the {{{field}}} statement where {{UILANGCODE}} is used to select translated text values for properties of the page.