You're.. supposed to buy the indie pack to support the indie developers and play some great games, with the portal 2 benefit as a bonus. Not because you want portal 2 to release earlier.
It wouldn't work anyway since Chell was in stasis during all of the events of the Half-Life 2 story most likely. Also I doubt that the headcrab in the tube was more than a small easter egg. Portal 2 is supposedly a thousand or so years after Portal 1. One of the main reasons for them doing this was so that it wouldn't…