So I stole some of Luc Danton's sequence advice to sFuller and Pubby (about sequences), and I generated this "stop messing around with operator," version:

#include <iostream>
struct lua_State {};
template<typename T>
T CheckLuaValue( int n, lua_State* l)
{
    std::cout << "arg[" << n << "] gotten\n";
    return T(n);
}

template<int ...>
struct seq { };

// generates a seq< First, ..., Last-1 > as "type"
template<int First, int Last>
struct gen_seq
{
  template<int N, int... S>
  struct helper : helper<N-1, N-1, S...> {};
  template<int... S>
  struct helper<First, S...> {
    typedef seq<S...> type;
  };
  typedef typename helper<Last>::type type;
};

template< typename X >
struct MemberFunctionWrapper;

template< typename F >
struct MemberFunctionHelper
{
    typedef F MethodPtr;
};
template<class InstanceType, typename ReturnType, typename... Params>
struct MemberFunctionWrapper< ReturnType(InstanceType::*)(Params...) >
{
  typedef MemberFunctionHelper<ReturnType(InstanceType::*)(Params...)> Helper;
  typedef typename Helper::MethodPtr MethodPtr;
  static MethodPtr& GetFunctionPointer() {static MethodPtr pFunc; return pFunc;}
  static InstanceType*& GetMemberPointer() {static InstanceType* pThis;return pThis;}
  template<int n, typename Param>
  static auto GetLuaValue( lua_State* luaState )->decltype(CheckLuaValue<Param>(n,luaState))
  {
    return CheckLuaValue<Param>(n,luaState);
  }

  template< typename sequence >
  struct call;

  template< int... I >
  struct call<seq<I...>>
  {
    ReturnType operator()( lua_State* luaState, InstanceType* instance, MethodPtr method ) const
    {
      return (instance->*method)( GetLuaValue<I,Params>( luaState )... );
    }
  };
  static int CFunctionWrapper( lua_State* luaState)
  {
    MethodPtr func = GetFunctionPointer();
    InstanceType* instance = GetMemberPointer();
    ReturnType retval = call< typename gen_seq< 1, sizeof...(Params)+1 >::type >()( luaState, instance, func );
    return 0;
  }
};

struct test{ int foo(int x, double d){std::cout << "x:" << x << " d:" << d << "\n";}};
int main(){
    typedef MemberFunctionWrapper< int(test::*)(int, double) > wrapper;
    test bar;
    wrapper::GetFunctionPointer() = &test::foo;
    wrapper::GetMemberPointer() = &bar;
    wrapper::CFunctionWrapper(0);
}

now, note that the calls to CheckLuaValue can be out of order (ie, it can ask for arg 2 from Lua before arg 1), but the right one will be passed to the right argument.

Here is a test run: http://ideone.com/XVmQQ6