Daycare at work would be wonderful. I was lucky and found daycare ~ 1mile from the plant, that could support my hours, even during 2 outages. But this was offsite - nothing to do with the company.
When you factor in that most plants only do 1 outage every 18 mos - 2 yrs, for about 3 wks, the cost and liability of setting up daycare to support the few workers that would use it just doesn't make it feasable. Licensing and inspection from state agencies takes weeks to complete. Most house folks already have things setup, since they live in the surrounding 20 towns, and bringing the kids to work isn't usually the best thing for us.
As you mentioned, it was you and another person that were discussing this - in order to make daycare pay for itself, it would take ~ 10 kids, at a rate to pay for the time to get licensed, and do the background checks on the daycare workers. That would not be cheap.....
Mike is probably right - you may want to rethink your priorities regarding work. If you add up your expenses, and the turmoil being on the road can do to a little ones routine, you may be better off changing careers, or at least going long term DOE for a while.
I am not saying this as someone that has no kids - I have 2, pre-school and kindergarten. I understand the stress of having to work outage hours, and not see my babies. And as a house mouse, I don't have the layoff periods to catch up.
Good luck with this issue, but don't expect much - you are a very small minority, and the power plants really are not in the business of accomodating the supplemental workforce - they will just find someone that can deal with the outage next time.