Now for the interesting part -- storing my 20D attached with a Canon 100-400; my main sports photography setup. As shown in the picture, it is certainly no problemto!
(Total length from eyepiece extender to front lens cap: 276mm,
Diameter of hood: 115mm)

The Canon 100 Macro can also be placed comfortably in a standing position instead of lying down as shown.
(Total length from Canon 100 Macro's rear lens cap to front lens cap: 140mm, Diameter of 3rd party hood: 92mm)