For a fixed size array you can use a define a struct and use cfg_struct<T>:
CODE
struct my_array_struct {
COLORREF colors[16];
};
static const my_array_struct g_default_value = {...};
static cfg_struct<my_array_struct> g_var(some_guid, g_default_value);
Otherwise you can use a list based cfg_var. See cfg_structlist_t<T> and cfg_guidlist in foobar2000_sdk_helpers for examples.