Are there any stubbie sleeves for the 4l short neck growlers. It would really crazy if it had an attached soda stream sleeve, one could throw the system over ones shoulder

Hey Dean. Thanks for the question.
You are in luck, the 5L sleeve will fit it! It doesn't have a Sodastream pocket but that can be easily retrofitted. If you are wanting to make it more portable you can't beat the mini gas canisters though. They really aren't that expensive and they do save so much room.  One canister does 4L. 

We also have 4L insulated kegs now as well. They are shorter than the growler and don't need the reducing adapter on the top. Let me know if you want us to send some images through, we only have a limited amount at the moment until the full shipment is here.