I think you should randomly take between one to six hp damage for each ten feet you fall, ignoring the first ten feet of damage and capping the damage at 210 feet. Also, you can ignore another ten feet if you land properly. And if you have natural kung-fu skills, you can slow your descent, possibly the entire way, and take no damage. Oh! or we could crank up the gravity and make it one to TEN hp damage for every ten feet, capped at 210 feet. Also, kobolds. heheheh!
It's something like sv_realisticfalldamage. You can turn it on or off. We had it on the BSID servers.