I am running buddyPress 1.7 nightly on a multisite install with buddyPress running only on the root site.
I have tried both network activating, and also just activating the extended settings plugin on just the buddyPress site, but neither approach shows the network tab on the settings page.
This one is strange because in the past, I was able to see the extended settings tab, using buddyPress 1.7. I am not sure what changed, if anything, but for some reason, now I am not able to see the extended settings tab.
I do not see any errors in either the browser or the log files, so I doubt there is any error involved causing the tab to not display. This leaves me with little to nothing to do in order to track the problem.