This is all kinda dumb.
You can mix ANYTHING in enough of a quantity and it'll be high calorie.
How the hell can you even drink something with oats and peanut butter?!?!
These suggestions would leave you so stuffed you would eat LESS overall food.
The key is to use things beyond calories that will put on mass. In that regard the absolute very best product has not been mentioned. It is the ONLY product which contains Super plasma protein, creatine, NO2, HRS, and oganic whole egg. Add it ISN'T FILLING.
Right here:
http://proteinfactory.com/shop/product.php?productid=145&cat=0&page=1