The kits Marke mentions and there a few available
http://www.astrosystems.biz/telekits.htm
http://astrosky.homestead.com/index.html
http://www.dobstuff.com/
are mostly ready to assemble with a little work, the atm section here is
has quite a lot of helpful builders who stop by to.
Does Peter still have the second 18" primary still on hand?
great value as the cheaper commercial offerings are sooner or later you will have to do some work on them , some of the great mods people launch into are easily no more difficult than assembling a kit scope.
good luck