Only to those who aren't inquisitive. There are several old promotional videos that have been put up on YouTube, old screenshots and brochures have been put up

Only to those who aren't inquisitive. There are several old promotional videos that have been put up on YouTube, old screenshots and brochures have been put up on web pages, there were the recent 'bringing back to life' videos and talks/demos by many of the people involved at the Computer History Museum etc. The information is there, you just need to look for it. Search on 'Lisp' along with 'Lisp Machine', 'LMI' or 'Symbolics'