Sports cameras do it all
 

Whenever I go touring I am always amazed at the mount of heavy and bulky camera equipment that I end taking with me, even though I try to reduce it I still end up with a tank bag full of gear.
I am used to carrying DSLR and Video camera plus a sports camera mounted on my crash helmet then add in spare batteries and chargers and other accessories = problem.
Now I have bit the bullet and have decided to carry just one camera, thats my GOPRO 3 Black version. It can record high quality 2K video and take 12mb photographs. If you add the monitor back pack then you can frame the shots and review the videos with sound when ever you want to.
The quality of these cameras is really amazing and combined with the small size they take a lot of beating, after all they are used by major TV and film production companies.
Now all I carry with me is one GOPRO camera plus spare batteries and a charger which fits inside a small bag saving space and weight plus they are more rugged than most video and DSLR. The camera is about the size of 2 matchboxes with loads of different mounts for different possibilities of mounting locations. I can also charge it off my bike auxiliary power socket.

Not only when touring but also when out and about they fit inside a jacket pocket so you are never without a camera to capture that special shot or event.
Well worth a rethink for your next trip!!!?c?

You're going to lose a hell of a lot of dynamic range, image quality, resolution whilst sacrificing the high ISO/low noise ability of modern sensors found in modern dSLR's. I also don't understand why someone would take both a dSLR and a video camera, because high-end Nikons and Canons make professional level, high-def video files. You also sacrifice access to superzooms, fast primes lenses like 1.4's, wide-angles, fisheyes, etc. Of course, it all depends on what you want to photograph. Best thing to remember about great photography is "f8 and be there" :)

SLRs will die or minimize in numbers like camcorders has to be in near future. New mirrorless cameras and snapshots has also f/1.8 and interchangeable or zoom lenses. Agree on camcorders though !

Not sure if sensor size really matters ! Even some is full frame today...

Full frame sensors can be useful as they offer better control over DoF (depth of field), and as far as dSLR's go, give you access to proper wide angles, though of course, new-breed mirrorless cameras are changing the playing field. As for image quality, I'd agree, especially with sensors like the X-trans by Fuji, the need for full frame in today's market is debatable. While smartphones will kill off compact cameras, I think m3/4 will eat into the sales of dSLR's.