Danny makes a great point. If you are packing wide/normal/short tele, the SL2 becomes much less expensive etc than swapping systems. I looked at this idea (and still do from time to time) and end up at the Olympus 4/3rds system (Panasonic is terrific but seems optimized for Vids that I just do that much of).

The cost of swapping systems net to net is just so high. Using a sling style strap has made lugging the big stuff a lot easier.