I, for one, would be very glad to have another way of running a Macintosh Plus logic board without the original AB, since both my ABs have failed on meI fail to see how putting that #%>$^%|@$ A/B away in a box for safekeeping/preservation could be considered ruination.
That sucker and the MoBo always needed a fan or a MacChimney to work very long after the convection cooling design's airflow got borked anyway.
I was just considering that, from a collector's point of view, having a classic Mac without its original AB is a suboptimal solution, and one that would not employ the integrated CRT anymore. In order to replace the analog board but still use the original CRT, one would have to design a video circuit that mimics the functions of the original, but that is somewhat beyond the purpose of the "external video" hack (and would probably require a good amount of reverse engineering anyway).
Still, I'd be very interested if someone decided to go ahead and try to design such a board, even focusing on just having the external video output working for the time being! All the proposed concepts are very intriguing, but are very much beyond my electronic capabilities...