how about using a small plate heat exchanger in a counterr current set up outside of the pc. If a small fridge or thermally sealed container could be used a mixture of dry ice and acetone/some type of alcohol could drop the temp to -78 degrees c, this is then pumped by a small pump into one side of the heat exchanger while the hot water/ cooling liquid is pumped in the other side. providing the correct size of exchanger and the correct flow parameters are used (i.e. flow rate, pressure.) it is possible to lower the internal cooling liquid to around -60 allowing for heating in tubes. now condensation is a problem but im sure it can be sorted in some way.