The ones I had before were built by an electrical engineer who went into overkill mode when he made them. And you're right, they were not cheap. The metal box they used was 18" x 24" box designed for exterior breakers so not small.The one that is unavailable has been replaced by their new model for $500 + Shipping and Taxes. You are looking at $700 by the time it's installed and that is not even in a waterproof enclosure.
Unless you can find the "on-island fabricator" of Automatic transfers that Pichardo says he used. But I doubt that $200 will be the price and the quality - anyone's guess.
Based on what I have seen of electricians and car mechanics so far, 'quality' is not a worth they have yet been taught
That was back in the 80's and they cost almost 1K back then. I was younger and dumber back then.. lol
They were very well constructed and had all of the bells and whistles.