GrnEyedDvl wrote a few aging scripts for 4, 6, and 12 TPY.
http://www.twcenter.net/forums/showthread.php?t=175383
If you don't want 4, 6, or 12, it's pretty straightforward to adjust his script to whatever you want.
Edit: Actually, your title confused me. What people call an aging script on here is a script that changes the rate at which characters age. If you want to make them live longer, I don't think it can be done via scripting. If it was possible, it would be a simple text edit in descr_campaign_db
You can try fiddling around with some of those numbers that seem relevant.