I know 2 drinks that you would supplement your normal diet with.
Whey To Go - is am excellent one! Its quite expensive, but it tastes lovely and the ingredients are all natural and nutritious.
Or if you didn't want whey:
Hemp protein - this is delicious, it really has a unique flavor when mixed with milk. Hemp is highly nutritious with natural hemp oils as well as protein.
You can buy both of these in Wholefoods, Planet Organic, and at a lot of online stores.
You wouldn't use a "protein shake" to replace a meal though, because it isn't balanced, and you would miss out on major nutrients, if that is all you had.
A meal replacement drink isn't just protein, it has fats, carbs, protein, vitamins and minerals in to provide a complete meal.
If you want meal replacement drinks you could go for:
Ensure Plus, Fortisip, Absorb Plus, Fresubin or Boost.