Camera Bag - Is a Custom Solution the Only Real Option?

[Tsundere]

Could a bikepacker’s framebag be adapted with foam padding? A suspended and well damped location potentially.

The main advantage would be its proximity to the bikes natural pivot point. Anything stored here will be least affected by all cycle movement and impact shocks to both wheels. It's also the safest place if the bike is dropped, as pedals and handlebar will do much to keep the framebag from making contact with the ground.

 

[ferrus]

That’s what I was thinking. The only problem might be the limited width available, especially with any protective padding.

 

[Tsundere]

That’s what I was thinking. The only disadvantage is the limited width available, especially with the protective padding.

With the lens removed most cameras aren't too bulky, with the right kind of foam, nothing too thick and spongey, it should be doable.
You could make bumpers that attach to the outside of the bag with velcro. Again, using good quality low profile shock absorbing foam cut to shape.

 

[Tsundere]

If I were going to take the frame bag route, I'd go the whole hog and get one custom made for my frame to ensure a snug fit, with straps in all the right places to keep it well secured. Alpkit do this and there are others out there.

If necessary attach your bottle cages elsewhere, if you don't have bosses on the underside of the downtube there are plenty of cheap solutions like stem, rack or saddle mounts.