An interesting thought has occurred to me (but IANAL, so...):
Might it be possible for Castle and ROL to agree for sales of RO4 by third parties (ie STDevel, VA and so on) to be allowed to continue with the royalties being paid into escrow for collection by whichever side wins the arguement? This might allow people to continue selling RO4 machines without either Castle or ROL having to admit fault (until things are legally settled), and would certainly make life easier for everyone else in the market.
This is obviously more of a problem with physical ROMs (since someone paid to have those made) than for VRPC, but it might allow things to be freed up temporarily? (But, as I said, I am NOT a Lawyer and there may be serious legal reasons why it simply can't be done.)