Hi! Welcome to GEH!
1. As far as I know the location of the cache is hardcoded in GE, so the only way to do it would be to store the entire GE Install on the network.. or get into the sourcecode and make changes.. Maybe you should suggest this as a feature to the devs over at GEC
2. There is no GE version for UNIX, however they are working on an OSX version currently that can be more easily ported if you are up to the challenge.
Hope this helps!