Possible to add a new object type (not subtype)?

Is it possible to add an object type (not subtype)?  

In case you're wondering, I have a very large DB and am about to add 10,000 new objects to it.  I'm interested in setting them off as a separate object type because (1) I'm using Lucene search and I want to be able to segregate them and (2) I'd like to design a custom main "entity" table for them.

Thanks very much.