Good ol' B&H had one and I just received it today.
I must say the Slingshot 300 is quite a bit bigger than the 200 and holds a lot more stuff. Therein lies the danger. The point of my using this type of carry system is to have a lightweight, quick and easy to use bag for travel duties.
The waistbelt makes the whole package easy to wear and having the weight evenly distributed will allow me to walk all day and at the same time spare my back.
Here's hoping it works as intended. My wife says it better be the last bag for awhile or I will need to move to the garage.
Happy New Year everyone!
John