If you are within driving distance of Ohio you may want to atten the anual ETF convention this spring. Last year my goal was to get a porthole, and I returned with a nice Zenith that only needs two parts asside from a recap and cabinet work.
The web page for the meet is here.
http://www.earlytelevision.org/2011_convention.html
there is literal tonage of vintage sets brought there anually for sale, and I came to both meets I've attended with a goal of getting a cretain type of vintage set, and both times I got what I wanted.