Please note that the en_GB.ISO8859-15 locale *is* supported by the X server (at least in current CVS). It uses the ISO 8859-15 character encoding, which makes the Euro sign available. However, it differs from an [EMAIL PROTECTED]'' variant because it uses the Pound, not the Euro, as the currency symbol.
I believe that en_GB.ISO8859-15, not [EMAIL PROTECTED], is what you want. The creation of an [EMAIL PROTECTED] locale before the UK commits to joining the Euro zone would be a political statement. Juliusz