I bought my Beseler 67 about 30 or so years ago, and it still works well for me. I use it for everything between from 35mm through 6x4.5, 6x6 and 6x7, although I actually have a carrier for 110 film.
For the last couple of years I have been using a dichroic colour head for VC black and white, but for most of the time I just used a condenser head and filters.
If you are using a condenser head, all necessary condensers are included.
If you use a dichroic colour head, there are two different mixing boxes - a 6x7 that can be used for all formats, and a 35mm mixing box that will give you shorter exposure times for 35mm and smaller.
They have, over the years, come in a number of configurations (single small column, single large/massive column, double column) and the dichroic heads have varied over the years (some have built in voltage regulators, while others require a separate voltage regulator).
They take their own lens boards, and negative carriers, but they are both available new, and relatively easy to find used (although certainly not as plentiful as the 23C accessories), because they have stayed the same throughout the years.
The bulbs are fairly standard and available, but they are special purpose bulbs.
Beseler still manufacture them, and you can actually talk to them:
http://www.beselerphoto.com/
I recommend them to anyone who is in North America, and is happy with a maximum negative size of 6x7.
This looks to be an okay deal:
http://cgi.ebay.ca/Beseler-Dichro-67s-67-s-Film-Enlarger-w-extras_W0QQitemZ190282654386QQihZ009QQcategoryZ29985QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Matt