Did anyone tried to modify the code to have pardiso running in out-of-core mode? Apparently seams simple, just to set iparm=1, has described in the following link:
(I know, the devil normally is in the details!)
This is also a suggestion to improve CalculiX as an out-of-core option would certainly allow for much larger models (at the expense of speed off course).
Maybe a simple way to do this would be to allow another solver option, for example SOLVER=PARDISO-OUT-OF-CORE. This is again just a suggestion.