Ive been using WinUAE again recently and was struck by how nice it is to use for oler Amiga stuff compared to my real A1200. What it lacks in "authenticity" is easily made up for (Imo) by across the board compatability and speed, (and no horrible floppies).
It really makes me think that a fast board running UAE and AIAB (or Amiga Forever, or AROS) in an original case would be a nice blend of old hardware authentic feel and new hardware power.
check this for the ulimate C64 conversin:
http://www.mini-itx.com/projects/sx64/default.asp?page=3Have Fun!