Denis, curious why you're particularly interested in the Roland RA-800. As a former RA-800 owner myself, I assume you've already read my opinion of it : http://www.synthzone.com/ubbs/Forum37/HTML/009960.html , but if you still really want one, here's a link to what it's currently going for on eBay:
http://www.synthzone.com/ubbs/Forum37/HTML/009960.html

I sold my RA-800 for around $900 US dollars several years ago. I think you'll find a lot better sounds & styles on its succesor, the Roland G1000, though it of course isn't available as a table unit.

Scott