Thanks, Ben. I wasn't aware of the 'visit page number' dimension before now but sounds like it could certainly do the job!

I totally agree, it would be very useful to be able to create segments based on criteria present in the entry hit of a visit. For example, we'd like to create segments based on the user's login state on entry, e.g. 'Visits where the user entered the site in a logged in state', and the best way I think to do this would be to use a visit container, then nest in an 'entry' container (which doesn't currently exist), then add our custom evar to track visitor login state.