I haven't, but that doesn't mean that there aren't people working on this sort of idea.
Let me be clear, and this harkens back to what Georgina was saying at the beginning: You can't actually have a vibrant economy without the care economy.
What we're really talking about here from an economic point of view is the production, development and maintenance of human capabilities or human capital. When we think about the stresses and strains that are created in the unpaid care that's taking place and the fact that unpaid caregivers are actually taking pressure off the health care system and the education system, we see there is an opportunity cost associated with not investing in helping to support those unpaid workers.
What I haven't seen, though, is the compelling piece of economic research that would put the dollar figures around it that would then help you design effective fiscal strategies, such as providing the sort of tax incentives or subsidies that you're referring to. It certainly merits significant investigation.