FWIW, I bought the LensCoat RRS PG pouch for the RRS gimbal. When filled and rolled up, it's the size of a 300/2.8 lens. Turned out the pieces (including the nodal slide) all fit in a Lowepro Lens Exchange 200 AW, which is sized for a 70-200/2.8 and handily sliplocks onto the outside of a pack...and the case is less than half the cost.

http://community.the-digital-picture...ead.php?t=7018