Re: 1.2 can't function independently
I think I know what you’re after and my answer would be – not without customization.
You could have your WP theme as the parent and bp theme as the child. Even with this setup, you’d need to modify the BP theme so it didn’t interfere with the parent which is what you’d want folks to see most of the time.
I encourage you to take a look at the structure of Buddymatic where Ron took Thematic and added the key buddypress templates and functions to create a “unified” parent theme. You could do that or leave the WP stuff as the parent and put your BP stuff as the child. Remember the child “overwrites” the parent so where you don’t want the parent overriden (e.g. home page), you need to remove/rename that file in the child.
I know it’s a bit confusing, but take a look at thematic and the new parent/child structures.