With all of the other regions these are popping up in, with all different labels and sometimes different casings, but seemingly the same program, I think I will postulate...
NTDEC under pressure from Nintendo in asian countries decided to liquidate their excess stock in chipboards and even complete shells, to all kinds of foreign countries. There've been instances in south and north america, and Europe really wouldn't be out of the question.
I think NTDEC may well have handled the initial USA distribution. Under the name Caltron, they may very well have been a few of these taiwanese guys or a representative of them, in order to maximize profit instead of just "pawning them off." But after it didn't work, they liquidated...to another TX group calling themselves Myriad, and to some other distributors in other countries.
I'm thinking this is the case after Xevious posted a shot of the inside of his new brazillian 6-in-1 and it's definitely a "caltron" board. It's too much of a coincidence that there are multiple "alternative" 6-in-1's all over the friggin world under different names/distributors...even in the USA.
So, yes, I think the Myriads may date from the time these were liquidated off to Europe and Brazil and possibly other places. Since the ROM says Caltron, I wonder if these others do as well. That would make Multi-Acao and this blue-back one brothers of the Myriad, and sons of the Caltron.
I think regardless, Caltron/Myriad wasn't the beginning, rather near the end of the pirate chain, like leaves on a branch.
And I also am starting to think that their inclusion as canon is silly because of this. As in, these and Panesians, but not early Sachens or other import multis. But this isn't the first time that's been said, and anyways it's a potentially fun and inflammatory discussion for another time.