Not as common now as at the turn of the last century.

Ansel Adams made himself one.  Pictures and description are
in 'The Print".'

I know of no commercial unit.  Beseler does make an
8x10 adapter for it's 4x5 enlarger.

--
Nicholas O. Lindan, Cleveland, Ohio nolindan@ix.netcom.com
Consulting Engineer:  Electronics; Informatics; Photonics.

DeVere 5118 is 8 x 10
DeVere Vulcan is 10 x 10
DeVere 508H is 8 X 10
DeVere Metro is 10 x 10
Omega Chromega F is 10 x 10
I suppose all of these still are in production.

Victor Falkteg

Yes, there is such a thing as an 8x10 enlarger.  New, they are quite
expesive and large.  Beseler makes a head for their 4x5 enlargers that
will do 8x10.  I have heard that is is not really very satisfactory as
8x10 heads go.

Aristo makes a variety of cold light heads which will cover 8x10.  I
believe they have up to a 12x12 cold light source.  

If one is handy with the tools, I have seen a cold light source mated
to the business end of a 8x10 view camera and used as an enlarger.
Another poster mentioned smething Ansel Adams made in the 40's which is
very similar to this approach.

Also, since many print shops are phasing out silver based printing
sources, a horizontal camera could probably be aquired and adapted as
an enlarger for a reasonable cost.

Jeff

 I don't know of any currently made adaptors but its not
too difficult to make one.
You must make an adaptor back to take a negative holder.
This can be as simple as a board with a slot to take a glass
sandwich.
 I've thought about lamp houses considerably. My current
idea is to use a metal box with the sort of fluorescent
lamps used to replace incandescent reading lamps.
 The lamphouse is mounted on a simple frame which also
takes the camera. This way the camera does not have to
support any weight but its own.
 The camera must be one with front focusing.
 The frame with camera and lamphouse can be mounted
horizontally or vertically if you have a sufficently heavy
duty tripod. Horizontal is easier.
 If you use my idea of fluorescent lamps they should be
allowed to run continuously and a shutter of some sort used
to regulate time of exposure. Fluorescent lamps change
output with temperature; they like to run hot, and are not
suitable for intermittant use.
 This sort of rig requires no changes to the camera which
can still be used as a camera, plus the whole thing takes
little space when disassembled.
 "Real" 8x10 enlargers are available used for not much but
are _very_ large. You really can not appreciate the size of
an 8x10 Omega, Saltzman, deVere, Elwood, until you are in
the same room with one. You will think the Martians have
landed. If you have the room one of these guys will work
very well. Otherwise the adaptor will allow enlarging and
also making enlarged proof sheets without needing a ball
room sized darkroom.

10x10 enlargers are often free for the taking. Look around.