Announcing Condi as VP 2004 would go far to guard against this event.
But I think you're still thinking with too much decency. I don't even want to type it straight out, but consider. If the candidate herself lost a child, say right before her first debate (or at any time it started to get too dicey), it would be too cold and cruel to expect her to debate, campaign, etc.
Anyway, we all know her already, right? Surrogates could appear in her place shamelessly promoting her as the hard fighting champion of the little people...