I'm told that 2013 and later model Leafs have bidirectional energy capabilities and can be used with the Setec Power V2H unit and the Nissan V2G units (vapor-units???). Appears this is very worthwhile hack to use with a commercially available (~400 VDC) bus system (Pika Energy in particular). Pika has no interest however as they want to sell their proprietary (yes very expensive) battery. I don't really blame them however as they likely don't want to be involved in the already problematic battery degradation issues of the Leaf.
Since I'm not an electronics designer with any in-depth CAN, microprocessing, circuit board design experience, I'm simply hoping a DIYer or startup company will produce the basic design of the required controller. It seems you have mastered the external battery charge controller functions which would seem to be the critical factors in the design of the solar/grid based charge (discharge) controller. The Bolt purportedly uses PLC protocols over the DC bus to do the controls - that might be simpler? AND having a 60 KWH battery would result (my case at least) in almost total independence from the grid for my house with properly designed solar/backup generator system.
The arguments that such dual functional use of a large EV battery will significantly increase degradation would not seem to "hold water", IF the controller was "smart" and minimized the rapid and hot charging of quick charging AND the amount of overall rates of power transferred in/out over time from the solar system was relatively small compared to the normal driving habits. (likely TBD!)
My guess is that over the next few years, as most EV batteries become 300+ mile range capable, and most driver use 10% of the energy daily, this concept will eventually gain traction. May have to just be patient.
2012 Leaf SL; 36,000 miles. Battery replaced November 1st, 2016.
Rural cabin with 6750 watts Grid tied PV. Off-grid solar Leaf charging capable (level II).