In article <op.uhlqb7b29245dp / kool>,
  "Michael Selig" <michael.selig / fs.com.au> writes:

> - To my knowledge UTF-16 & UTF-32 are the only "non-ASCII compatible" as  
> Ruby defines it

ISO-2022-JP is another example.

> - To my knowledge no one actually uses UTF-16 or UTF-32 as a locale

They are not usable as locale encoding.

http://www.opengroup.org/onlinepubs/007908799/xbd/charset.html
| * The encoded values associated with the members of the portable character
|   set are each represented in a single byte.
-- 
Tanaka Akira