Not sure as I have never tried. However - if I had to guess - I would think they would possibly fall apart as the couscous swells quite a bit and (being full of liquid) it is quite squidgy.
I did meatballs for the kids last week and just mixed my meat (I used quorn mince), some wholemeal breadcrumbs, a beaten egg, chopped parsley and salt and pepper and some grated onion. I cooked them on a baking try in the oven and served them with a tomato sauce and spaghetti.
You could always substitute the spaghetti for the couscous??
Hope they work out and you enjoy them anyways but let me know how you get on - if it works with the couscous it could be one for me to try! xx