Sounds like your progressing well with CALF.
Thought.. can you access the file system? If so how about saving your objects in JSON format - then you have some fomr of persistance.
As for one object being in two locations at once.. Im not sure.
I know an object can only have one location..
.. and an object can only have one host (what its on in that location)..
.. but if the location was force to be different to the hosts location.. would that object appear on the host and in its own location.
Im guessing some recurive strictness on my behalf would limit that from happening but worth testing if you have the beans for it.
It could be a standard part of cow tho.. like a shortcut or symbolic link in linux.. interesting thought.. thanks.
PS did I mention I got the game Prototype? such fun running up the side of buildings.
Lucky me has a new notebook with a massive graphics card so Im happily playing relatively new games as max graphic settings.. its such fun! I have started on an endless quest to have a copy of all of the 'good games' - starting with Portal, then Half life, then Oblivion etc..