I ran against the arity limitation of 10 and to resolve it, modified tuple_basic.hpp to use the preprocessor package for all variable length argument lists (with macro BOOST_TUPLE_MAX_ARITY serving as a single parameter configurable from config/user.hpp). I'm not sure if this modification will be of general interest, but if so, where do I send it? Modified code has been tested with MSVC 2003 (7.1). Regards, ...Max...