Has anyone here actually replaced the back casing on their 3g? I've been very abusive to my phone and it has about three sizable cracks. they are in the usual places and given it was one of the first batch of white 3G's I would have had a try at getting replacement but it's out of warranty. I've looked at a couple of on-line guides to do the repair, and it seems like you need to do a complete tear-down of the phone to get the back casing off. Given the phone works completely O.K I'm reluctant to break it.