I'm not in no way, of possession of the credentials to give the OP's the reply he wants, but I've once seen Liquid Nitrogen cooling solution, which was actually a small flat chamber with the liquid trapped inside, which was serving as a "floor" for us to step over. To keep it cool at the lowest cost I believe that a magnetic cooling system was set up (don't clearly remember the occasion).

 It was serving as cooling solution for chemical reactors though, not sure if such technology applies to this case.

A quick search on google points me to this on first link: http://en.wikipedia.org/wiki/Magnetic_refrigeration

Have no idea about the costs

Happy new year

Edit: The Lab was located at University of Algarve in Portugal, department of Physics and Chemistry
https://www.ualg.pt/home/en