Using power from the HV battery

I was reading a thread on here about high output inverters and how the Prius 12v charging system is the main limit as to how many amps you can pull. I understand they used to make an inverter that hooked directly to the Prius high voltage battery and allowed you to use more power than was available through the 12 volt system. Ialso understand that it's no longer available.
Has anyone tried using an mppt solar controller? I've seen them as high as 200 volt input and 80 amp capacity and they can be paralleled as long astheyI have the same charging profiles, which if you buy the same model at the same time should not be an issue.
I would use them with some sort of battery as a buffer, perhaps two in series for 24 volts so you don't need to pull as much amperage... They do make 24 and 36 volt input inverters. By separating it this way this also isolates most of what you're doing from the car systems so less chance of messing something up. You can still use the car's 12 volt systems for normal stuff like things you would plug into a cigarette lighter. You'd probably want to put the system on some sort of fail safe relay to make sure to shut down completely when the car is off in order to avoid eventually draining your HV battery.
I have a ticket in with Renogy to find out if a 200 volt input controller can handle the Prius HV battery but can't imagine why such a small difference would matter at such a high voltage.
Thoughts? I have multiple possible uses for high power output from the car, from camping to running a space heater in a camper to backup power for my off-grid house or running a small wire feed welder.

 

Had to search for the price and finally found it in an article about it on a different site, yeah that's pretty pricey.
Of course the parts that I'm thinking of (1 or 2 mppt controllers, 1 or 2 12 volt batteries, one big honking inverter) are still over half the cost but can be split up and placed in different locations and if one component fails you don't have to replace the whole thing.
Of course your charging would still be limited to only 1800 watts although batteries would give you some surgeability.
I can see pluses to either way, might be fun to look into

 

Thanks, I wasn't sure where to begin asking and apparently wasn't having good luck with keywords either.
After a quick couple of glimpses, it looks like somebody's already talking about using solar controllers, hope to read some more tonight after work.