Those "archived" companies bring also other problems if they are not moved into their own package combinations:
As soon you install something that needs a reorganizations of the tables/creation of runtime with reorg, Baan will try to reorganize also those companies that are read-only in Oracle - this must be adressed as well - we just encountered problems with that (right patrick?).
Regarding using tables splitted by several tablespaces, yes, that is possible and several companies do it (keeping tools tables away mostly, or the financial tables). Just create the tablespaces in Oracle and then adapt your $BSE/lib/ora/ora_storage accordingly before creating the tables:
So, if you ever wondered what those '*' reffer to:
1st '*' field: table(s) ! - you can use wildcards here
2nd '*' field: company