Jobs - wouldn't it be great?

It's no secret I want to work less and stay home more. DH likes this idea too, except for the reality that we haven't yet figured out a realistic way to afford it.

I'm wondering more and more if we could possibly pull off something clever with contract work long-term, so that I spend 6 months at home and DH spends 3 months at home each year, with 3 months where we both work and the children are in care - sort of a reverse-summer-break.

This would actually work as a two-year cycle to maximize the time DH and I can spend at each job. In other words, DH would work for 18 months straight and I would work for 1 year straight, with three months of overlap at each end.

A plan like this has a number of hang-ups, and I've already thought of probably 90% of them and come up with decent solutions for most that I've thought of, with ease. However, there is one thing that absolutely must be in place before we deliberately attempt this, something that I am less sure how to handle:

Debt-free with three to six months expenses in the bank.

This is where this plan gets tough. A plan like the one I described has significant financial risk every three to six months, and we MUST have some buffer space! To get this, DH and I will need to work simultaneously for roughly two years netting $20K per year above our non-debt expenses before we can even start (obviously, we're not including mortgage debt here!). There are other ideas, but none that we can count on (e.g., start a business netting $20 to 30 K a year; have one of us work nights consistently; and so on). Even having us both work has a number of variables we can't control, like that DH has been looking for work for 8 months with no luck already and that childcare could eat through his income if hours don't work out.

Could we handle it? Is it worth it to put our kids in childcare for two years? Is there another way to get these $$?