Reagan's Ultra Scrap Semi Light Dob Conversion 17.5" - under $100
Original Big Boy Odyssey 17.5.  The altitude bearing height is 3 feet and the beast weighs over 200 lbs.
Holy Scrap!
A big one fits on my platform at last.  The bottom of the rockerbox has laminate on it.  They only thing betweeen the platform base and the rockerbox laminate is car paste wax.
See the black lines on the poles - resin joined 2 poles together.
All the holes are covered with kitchen counter top laminate.  I guess I should really only show / use it in the dark.   The 4 square aluminum extrusions cost 3 bucks from the scrapyard.  Two were joined together with a resin (I cut them in half).  You will never find ones like these anywhere.

I re-used the altitude bearings from Odyssey (they may not have been original)  They feel as good to me as an Obssesion 25.  The focuser is not my design, but it is a homemade dandy.   My "spider" is just a piece of aluminum.   The mirror mount is from the Odyssey.  I have a smaller secondary mirror than the Odyssey.

My major design goals were to lower the center of gravity, reduce the weight, spend as little as possible, size it for my equatorial platform, and break it down very rarely (I have a van).  Just 56 screws are used to disassemble the scope so that it could fit in a trunk - minus the 75" poles.  Yeah, go ahead and laugh all you truss types with your quick release levers.  Four guys with screwguns can put this together in an hour.