I tested the following scenario:

Created Db1 and DB2.  Owner of Db1 and DB2 is sa, meaning all objects will be owned by dbo.  I created application role Db1..AppRole1.  I also created Db2..Tble and add 1 row of data into it.  I granted login UserA connection ONLY to Db1 and DB2.  Granted guest connection to DB2 and enabled cross database ownership chaining to Db2.  Using Query Analyzer, I set the Db1..AppRole1 and performed "SELECT * FROM Db2..Tbl", which failed with lack of permissions.  So, I granted guest SELECT on Db2..Tbl and executed the "SELECT * FROM Db2..Tbl" again, which was successful.  Then I disabled cross database ownership chaining to Db2 (guest SELECT permissions to Db2..Tbl remain in tact) and executed the "SELECT * FROM Db2..Tbl", which was successful.

From the scenario above, I conclude that if I have to grant guest SELECT on an object, I do not need cross database ownership chaining enabled.  What I was hoping to accomplish was to use cross database ownership chaining without granting object permissions to guest or any other users.  Is this possible?