The items that I have in my system that I wanted the Notes for are non-inventory items - but I have created "Custom Fields" - and on the items listing screen, I can customize the columns to show up.  I am not sure how many Custom Fields that you can create - but for my use, it's just a quick note on the location of my item, so it ends up working out good for us.  

I hope this helps for your application.  Have a Great Day.