Well I've been around for a while and have a nifty Pulse Energy(later Trace) PC250 of about 1999 vintage. It's basicly a box with all required fusing(at that time, god bless Wiley) and an integrated 60 amp charge controller(PWM). It sure makes wiring simple!
Of course I'm thinking about this as I'm trying to figure out all the breaker runs for 3 Classic Charge controllers into a E-panel lite. I guess I'd also want to be able to add classic lites, with follow me to the main CC in panel, and that would pretty much mean having incoming breaker in the Classic lite.
Just something I was thinking about...
...now if I put a 6x6 junction box against the lower right with a 2 or 2 1/2 knockout and run the 3 classics into that, incoming PV at the top 2 1/2" knock out,+ to the left din rail out to the CC's, back to the panel mount breakers, at the top right...