Speaking of Sol disasters, maybe the option to start with an Aeather Rift in Sol could be funny (and maybe even useful for testing purposes).
No idea how terribly unbalanced that would be though.
Some people would no doubt consider it a challenge.
On a similar topic, a variant on 'Earth falls into the Sun' comes to mind:
Instead of being tied to a specific body, have it affect whichever (remaining) body is closest to the Sun. IE it starts with Mercury and works its way out. On the one hand the player gets a little more time before Earth goes bye-bye, but on the other hand Mars isn't much of a refuge because it is next on the list. The asteroid belt will take a while to clear before Jupiter starts the plunge, but its moons aren't very habitable to start with. No matter how you cut it, the objective is to escape Sol.
If that still isn't enough of a challenge then have it affect every body in Sol simultaneously.
