There's a bit of a padded divider in the bag I stowed the monopod behind and then I had another divider laying around I put between the tripod and the slider, a Rhino Pro 2ft; for further padding I put sections of chopped up pool noodles from the dollar store on the slider. I am exchanging the Pro rails for the carbon version because the Pro is way heavier than I had anticipated or desired, overkill for a GH4 or 5d3. I also ordered the carbon 4ft rails that I may pack in a PVC pipe to eliminate any bending in the bag. The required size of the pipe will likely leave room for a boom pole when I replace the Home Depot model I currently have, a telescoping pole for replacing lightbulbs I pipe-clamped a bolt to for a Rode zep.
That's just what I use to get stuff to set in my car, but if you need a hard case for air travel PVC in larger diameters might be an option. Pool noodles on the legs if you don't want it bumping around. Just have to figure out how to carry the thing once you've capped it.
I used to fly my sticks in a soft Portabrace slid inside a Nalpak. It is too expensive to do that anymore. Airlines kill you with oversize and extra baggage and not to mention delays if it gets misplaced. So keep this in mind.
I recently bought a Gitzo Series 5 set of Carbon legs that extend super high and are very stable for either of my camera kits. My Sachtler Video 14 head works wonderfully on them. Broken down the head and legs (74.9cm) closed fit in my hard side suitcase safely stored and arrive with my knickers and blacks.
The Benro tripod bags are incredible! One came with my tripod, but you can get one separate for $25-$50. They are soft-padded, so probably not ideal for airports/super heavy/very large/long long-term usage. Mine has lasted me for almost 2 years with no damage.