It would be beneficial to be able to specify in Europe that the European
Ordering Rules (ENV 13710 and its update, CR 14400), are to be applied prior to
applying the collation info for the specific locale. The EOR has been developed
for pan-European applications (e.g. those at the EU level), and it represents a
true delta to the default template of ISO/IEC 14651, main differences being
currency signs and the treatment of Latin letters. (The Cyrillic and Greek
scripts in 14651 are largely modelled to follow the guidelines of the EOR.)
I've been informed by the project editor (Marc Wilhelm Küster) that the delta
of ENV 13710 is available in machine readable form both in the 14651 syntax and
in the syntax used by the ICU (the latter having been written for an C++-based
XML query engine).
In addition to using the EOR as an intermediate layer, one still needs a layered
structure above. For example, one could expect a specific collation sequence in
Finland for the Skolt Sámi characters, and the rest of the Sámi characters
would use a pan-Sámi collation sequence (defined probably in the Northern Sámi
locale), and the rest of the characters would use the Finnish collation sequence
above the pan-European and ww sequences.
A similar structure would be beneficial for use with a number of minority
languages in different countries.