I know this topic is old, but I just tried to affect the value of @@rowcount using a trigger and I could not. I would insert 1 record into a table, then have a trigger select, insert or update many records (I tried all three) and the next @@rowcount that I ran after my initial insert would return a value of 1. An @@rowcount inside the trigger would return values greater than 1, but not the next @@rowcount in the scope of the initial insert statement. It looks to me like @@rowcount operates like scope_identity() rather than @@identity in the sense that it is scope-dependent. I got the same results in SQL 2000, 2005 and 2008r2.

Same result here:

http://stackoverflow.com/questions/7005225/sql-server-does-trigger-affects-rowcount