Symbolics stuff isn't as rare as the post claims; you can still buy the Symbolics OpenGenera LISP environment for running on top of DEC's UNIX on an Alpha. [0]
In addition there's a port to x86-64 Linux floating around that lets you run it on top of a 2007-era Ubuntu in a VM [1]. There was also the MacIvory series of expansion boards that were a LSI-based Symbolics machine that you could fit in a Mac and run OpenGenera in a window.
Dave Schmidt at Symbolics was still selling hardware (a complete system could be had for under a couple grand) up until a couple of years ago; last time I contacted him he said hardware sales were now stopped so that what's remaining can be used for service/support contracts.
I bought a Symbolics keyboard from him before that happened and wired up an adapter using a Teensy to give it a USB interface.
I know of a company in College Station, TX that used a number of Symbolics systems when they were new, and the owner refuses to get rid of them because they cost so much new. A friend that worked there until recently ranted one day that they were using one of the chassis as a stand for the coffee machine, and I wanted to cry.
(disclaimer: I own/run http://www.lispmachine.net)
[0] http://www.symbolics-dks.com/
[1] http://www.cliki.net/VLM_on_Linux [2]
[2] http://weblog.mrbill.net/archives/2008/05/18/finally-got-ope...