iPod Touch Headphone Jack was All Jacked Up; Jacked in a New Jack
iPod Touch 4th Generation Headphone Jack
iPod Touch 4th Generation Front Panel Replacement
The LCD cable which attaches to the logic board, is, indeed, very short. When reassembling the iPod, you may only be able to leave a small crack between the glass and the body to allow for enough space to reattach this cable. A plastic opening tool works well, but be warned: it takes quite a bit of patience.