[fnordfnordfnord]

>I'm curious if anyone's had experience negotiating a severance package up front?

Nope, it isn't popular here in Texas. I tried to negotiate for severance when working with a company who had previously surprise-fired me. They were determined not to agree to any future severance or anything named severance. I ended up baking it into a higher hourly rate. In the end they paid my severance wishes many times over, in advance.