SunPower AC w Microinverter or SunPower DC w SolarEdge

[adoublee]

I think you are oversimplifying and glossing over a couple factors. Rapid shutdown electronics on the roof, are quite simple, low power circuits, and much less complex than microinverters, and even less power density that optimizers.
Things that fail are High Power, Complexity, and Density.

here's a link to one such system. These have to be designed into a system, it's not an easy afterthought to add on.

http://www.midnitesolar.com/rapidShutdown/rapidShutdown.php

That is not one such system, that is THE go to system for trying to keep an "old school" string installation. Plenty of drawbacks to that systems.

SMA's version has been an unmitigated disaster. Years to release, and many reports of it randomly shutting down and requiring a reset on the roof.

Keep in mind the system needs to be listed for the purpose, so options are VERY limited.

The next phase looks to be string inverters that broadcast a trip signal over the DC powerline to Tigo devices via a standard protocal (Sunspec). Tigo might be a more simple devices, but is still electronics on the roof.

I'd want a system that is somehow capable of providing me array power when the grid is down.