I'm speechless.
You're prepared to add breakers to an electrical panel in order to charge your car? Aren't there too many different types to make that practical? Where's your adapter to make 240V from two standard outlets?
To answer the basic question: Yes, I am capable and ready to add breakers to a panel temporarily to charge a car if it was absolutely necessary. ;-) Though thus far it has not been necessary. And to be clear, I do not carry ALL of this around with me in the car. The NEMA 14-50 enclosure with the SOOW cord, strain relief attached to it, and breakers has never been used with my Model 3.
There are actually not *that* many breaker types in use in my geography. If you get an Eaton 240v 50a breaker they are actually cross-rated to a whole bunch of different manufacturers panels since quite a few folks use that same basic style and dimension of breakers. Eaton, Siemens, Square D, and Cutler Hammer (CH) style breakers probably would cover the majority of what you run into around here.
With that being said, I actually built that temporary hardwire setup back in 2012 for a very specific trip. A friend had a new Model S that he wanted to take to another friends Tree Farm that was under construction but he would not have enough range to make it home. The night before we went I realized my friend (building the house) had a brand new Siemens panel installed for construction and so I went out and threw that "Emergency Tesla Charging Station" together. I already had the SOOW cord from an old UPS so all I really needed was the 14-50 receptacle box and the breaker.
Given enough electrical knowledge, range anxiety is much less of a thing since you realize you can find a way to charge just about anywhere. ;-)
As to why I don't have a "Quick 220": I am not really a fan of this device. I get its purpose and use case, but I have issues: 1. It encourages the use of random circuits that likely have other (unknown) loads on them so it is easy to overload the circuit. 2. It basically requires the use of extension cords since you are trying to find two circuits on opposite phase legs in a house, etc... 3. It encourages the use of general purpose convenience outlet circuits that are daisy chained from one outlet to the next. This is lots of potential failure points.
If I am going to go to that much trouble and cost to charge, it is WAY easier to just hard wire into the panel.
Note also: I can take and hard wire into existing breakers that I "borrow" by unhooking something else. A couple weekends ago I stole a 20a 240v breaker to backfeed in a generator connection at my inlaws during a power outage. For EV charging I could do something similar. Say unhook the dryer or range or AC or something not critical... ;-)