[Moved to DR at the October, 2012 meeting.]

Proposed resolution (February, 2012):

This issue is resolved by the resolution of issue 912.

There is no limit placed on the number of c-chars in a multicharacter literal or a wide-character literal containing multiple c-chars, either in 5.13.3 [lex.ccon] paragraphs 1-2 or in Annex Clause Annex B [implimits]. Presumably this means that an implementation must accept arbitrarily long literals.

An alternative approach might be to state that these literals are conditionally supported with implementation-defined semantics, allowing an implementation to impose a documented limit that makes sense for the particular architecture.