Maxx... You say you need to add more... May I ask why? I think for many the 11R effects would be enough. I'm not convinced of that, though; I'm not especially impressed with them, so I can understand the desire to add something. That said, I should think it would be easy to find one unit that adds what you need in the way of effects. Your Korg A3, perhaps, or the Boss GX-700. There are any number of others.

But it seems as though you don't know what kind of effect you think you need. I'm just curious.