class A
{
private:
    A()
    {
        ......
        if( нельзя создать объект)
            isConstructed = false;
        else
            isConstructed = true;
    }
     bool isConstructed;
public:
    static A* Create()
    {
        A *tmp = new A();
        if(isConstructed)  
             return tmp;
        else
        {
            delete tmp;
            return NULL;
        }
    }
};

class A
{
private:
    A(bool* isConstructed)
    {
        ......
        if( нельзя создать объект)
            *isConstructed = false;
        else
            *isConstructed = true;
    }
public:
    static A* Create()
    {
        bool isConstructed;
        A *tmp = new A(&isConstructed);
        if(isConstructed)  
             return tmp;
        else
        {
            delete tmp;
            return NULL;
        }
    }
};