I would like to see a hybrid inverter

I would like to have a hybrid inverter.  What is a hybrid inverter?  I'll over-simplify it, but let's say you have a 1000 watt PV system and a 1000 watt inverter but have a load that can vary higher than 1000 watts.  The hybrid inverter would supply the first 1000 watts from the solar/battery and the balance of power would come from another source (grid, generator, or another inverter).   Obviously I pulled the number 1000 out of the air, all I really mean is the ability to blend or stack two different power sources. Of course stacking inverters already exist, but sometimes the additional power source is going to be grid or generator.

There is a company that makes these, however they perform the opposite function that I want.  They are for supplementing inadequate RV or shore power.  Like for example the RV park only gives you 15 amps but you need 20 amps to run your AC or whatever, it will add inverter power to the grid power so you can run all your toys. I checked into it and they really aren't configured to use them like I described and are way over-engineered (with price to match) and complicated to use.