I'm not sure the 'glass cars will disappear, but this economy will sure tighten the availability of body choices as well as manufacturers. When you talk of '37 Ford, I'm not a big fan of the Coast to Coast or OZE phantom bodies either, preferring at least original looking as a beginning. Then there are the other avilable body styles - and in my part of the US (rust belt) there just aren't many salvageable '30s and '40s hulks to make hot rods from at any price. They are either scrapped and total rot or became race cars then scrap. That leaves you with the after market, either 'glass or Brookville type reproductions. Yes, you can still find a '30-'31 Ford, but these too are becoming scarce and expensive as the hot rod market is being pushed that way by the magazines.
Too bad about various manufacturer's disappearing - I always hate seeing a viable hobby business fail