You can use Tupperware to keep things in your go-kit. This way you'll be able to keep you go-kit neatly organized and able to find items quickly.
The Small Eco Bottles are a great way to enjoy water and other liquids. Rather than just take up space in your go-kit, you can store smaller items in them.
For a bowl to wash dishes and silverware I suggest either the Thatsa Bowl or Thatsa Bowl Mega. These large bowls can hold enough water to wash a few dishes. Get two - one for washing and one for rinsing.
These products and much more are available at Cathy's Tupperware Site.