The Atari "volcano" cone bezels are
here,
here, and
here.
The switch part is a lot harder to find, especially the LED kind.
Someone recently tracked down a part number for a switch assembly that works with these cones IIRC -- search "atari volcano switch" + limit the search time to 1 year and you should find the thread.
Scott
EDIT: Rockyrocket was the one who found the switches in
this thread -- reply #3 has several links to other switches at
VGP that might work.
Atari P/N 62-039 LED switches are
here.
EDIT2: VGP is now doing business as arcadefixit.com.