money

Hi UK-Y, long time no see.

DH and I making some long plans and considering a move back to the USA in the semi-decent future.  I know the sponsorship req's are 125% above poverty or 3x that in liquid assets.  So do I have to be making that amount - i.e., would I need a solid job offer for that amount in the USA?  Because I want to become a SAHM, just trying to figure out how the picture works when the US citizen is not the breadwinner.  (and the thought of $66,000 in savings plus $10,000 moving costs makes me feel ill)

It doesn't have to be you.  You can have a co-sponsor/joint sponsor who earns or has that much money.  When we applied for my UK husband's US visa I was only working part time in England so there was no way I would meet those financial requirements.  My best friend met the requirements and volunteered to be co-sponsor.  Visa was granted.   

Yes, you as the sponsor need to make the financial requirement (unless you have enough in your UK savings). If you can't, then you can use a co-sponsor. The amount that your spouse makes is irrelevant. There is no place on the paperwork where you would even list money that your spouse would make (if he has a job offer).

Does the co-sponsor have any obligations like they do for UK visas?  Just wondering how that arrangement works or if it's more just 'on paper' if you see what I mean.

This is what the affidavit of support form states:
Your obligation to support the immigrant(s) you are sponsoring in this affidavit of support will continue until the sponsored immigrant becomes a U.S. citizen, or can be credited with 40 qualifying quarters of work in the United States. Although 40 qualifying quarters of work (credits) generally equate to ten years of work, in certain cases the work of a spouse or parent adds qualifying quarters. The Social Security Administration can provide information on how to count qualifying quarters (credits) of work. The obligation also ends if you or the sponsored immigrant dies or if the sponsored immigrant ceases to be a lawful permanent resident and departs the United States. Divorce does not end the sponsorship obligation.

You can read more here:  http://www.uscis.gov/files/form/i-864instr.pdf