I'd second going the CSC/Mirrorless route. Lugging my FF stuff around just for a day out or even for holidays became a chore so wanted a smaller set up in addition to the DSLR stuff.
As Dan, I went to M43 with a Panasonic G5. I'm really impressed with it. Importantly I can get the M43 body and three lenses in the same space as a gripped D800 inc 24-70. But it's the performance that's really impressive. Autofocus is lightening quick, low light performance is very good and between 7 and 100mm (14-200mm FF equivalent)you've got highly regarded, fast glass. Also, for me, the DSLR shape of the G5 felt really comfortable in my stupid fat hands. I really loved the look of the smaller Fujis but they were just too small for me.
Mark