Our good friends at CrumplePop just released a new Final Cut Pro plugin file kit (?), Lumineux which emulates the light leaking effects of old lenses. Take a look:
While the usage in the demo clips may be a little over the top, this is something that is getting quite trendy (if not, why would they have made the product in the first place?) with the increasing popularity of mounting old lenses on HDSLRs.