I got my FIL the Huskavarna case for his Stihl. for all the reasons you mentioned the Stihl case is all rounded and does not pack well, but the huskavarna case is a square box with the chain saw bar sticking out. its a bit big but it does hold everything you will need.
For myself I built a plywood box 36" long and just big enough for my Stihl 024, it has a small area to hold some oil, gas, files and spare bits. The concept was I could ask some one to "go pick up my saw" and they would return with everything I would need to deal with a down tree. Well that concept worked great until I fell a tree right onto the box.
Now I have the 024 and a 032, and I find the best way to work is to take both saws, the smaller one to limb and the big one to buck.
My plan is to pack a milk crate with spares and tools and just keep the saws loose.