I have a '70 Parisienne convertible sitting in my yard that someone has done major panel replacement on. They didn't finish it because someone must have looked under the car and found that the frame was too far gone and also needed replacement. Be careful what you get yourself into.
Even if you have the skills to do the rebuild, probably the most economical way to take on such a project is to find a 2dr. HT with a good body and use that body by taking your convertible parts and put them on the HT body.
You can't beat dragging home 1 or 2 models similar to the one you are working on because you will always need other parts and there is a much better chance you will have them instead of searching around.
'66 Electra Convertible would be a nice car!