My wife and I travel on a regular basis and, of course, photography is an important part of our excursions. At this time I am using a 1D-X, which I absolutely love, but there are times when the weight, appearance and size of this camera make it impractical and/or unsafe to carry. For those reasons I am looking for another camera or body that would be more practical to take when the 1D-X would not be appropriate.
Image quality is a major consideration.
I sure would appreciate some suggestions on what might be an acceptable addition to my travel equipment.
If you want image quality at least as good as you're getting from your 1Dx, want to be able to stick with Canon lenses, and don't need fast autofocus, I would recommend a Sony A7/7r (plus several spare batteries) + metabones adapter (or forget the adapter and buy the two native primes, which are small and light by Canon standards - the remarkable resolution and sharpness of A7r + 55mm 1.8 allow for heavy cropping and may allow you to forego anything longer - and provide much faster focusing). I doubt anything as small comes close to the image quality such a combination produces (few bigger cameras do either, for that matter).
If APS-C will do, the SL1 has excellent image quality by APS-C standards, and if you only take the smaller Canon lenses with you it should be pretty inconspicuous. Since you already own Canon lenses, unless they're all big I don't see much point in trying another brand for APS-C. (I seem to be in a tiny minority in not being impressed by the image quality generated by Fuji's X sensors, though maybe the newest one will be better.)
If you want small + light + inconspicuous and the ability to change lenses, and don't need FF quality, one of the better Micro 43 bodies (esp. Olympus OM-Ds, with their excellent IBIS) seems by far the best option to me; compared to even most APS-C lenses many of their lenses seem almost weightless, many of the lenses are excellent, and the image quality compares favorably with APS-C.
If you want something that will literally fit in a pocket, the Sony RX100ii (or whatever the latest one is) is probably the best.