Found it. has_static_member_data
and has_static_member_function
from the Boost TTI library.
#include <boost/tti/has_static_member_data.hpp>
BOOST_TTI_HAS_STATIC_MEMBER_DATA( value ) // Generates class template has_static_member_data_value
...
has_static_member_data_value<Foo, int>::value; // returns true
has_static_member_data_value<Bar, int>::value; // returns false