Alternative cameras?

Has anyone had any success using cameras besides the Canon SL1 DSLR? Many of the sites selling that model list it as no longer available, and my group is interested in getting a newer camera model anyway. I ask because none of us have much experience with photography and we don’t know if other cameras would be incompatible with the lenses, POCS, camera box, etc.

Other similar Canon DSLR cameras should work fine. The models change so often that it is hard for us to keep up with detailed model number recommendations. The two main constraints are: 1) does gphoto2 software control it (probably yes for common camera models), and 2) will two of the cameras fit in the box?