It`s easy to make one.
1. Rods, sleeves on them, and thumb screws: Look in your scrap box.
2. Bellows: Agfa or Bogen regular big square one. $50.
3. Front shroud (since rectangular not round or square):
Black metal or shellacked manila sheet glued on the front and with lamp black or tar. The hard part is working in lens cables.
4. Additional miniature screws and nuts: From machine shop, or Gun Smith, or Watch Repairman, or saw, make, them right out of a dead hard drive.