Nik - My ds does this too and I know what you mean, it is like the end of the world if he doesn't get that last hug or kiss! It's so sad!
A few things that have worked for us are to tell him how many more he gets, or better yet, asking how many more he needs and then doing that. Sometimes we make it all goofy and when he says he needs tem more, we do ten really fast kisses all over his face fast and make big kiss sound effects. It sends him into laughter and he is happy.
We also have asked him to lay down, sing his ABCs to himself (or any song she may know, or she can count, go through all the animals she knows, etc) and if she needs another kiss, to call then. 9x out of 10, ds is asleep before it gets to that point.
It's a bit irrational at this point since the kisses and hugs are emotionally charged and not due to stalling, but if you are aware of which she is doing that night, you could give her passes - however many cards with kisses (pics of lips) and hugs (people hugging) on them and tell her she has that many to use, after that, all gone. You'll come give kisses before bed.
One thing I never do with ds is relate time to when I'll be back. At this age they have no real time concept, so use activites to relate to when you will be back in.
And goodness, I hope it's a phase too! We are at about week 3 or 4 of this as well. Some nights are better than others, but still!
