In my experience, I've found that 3 to 6 month contracts work best for this, as it gives you a good 9 months to a year to relax before you need to start thinking about work again.
As you've noticed, there are no other professions that pay this well and are in this high of demand for talent. Think very hard before you throw that away to drive taxis full time.
Since you say you've been doing this for 12 years, you no doubt have a few dollars saved away (especially since you claim not to have had a "life" during that time in which to spend your money.) I'd recommend forgoing every one of those job offers for the moment and taking a good year off starting today. Go travel the world and find that life. Come back when the money starts running out or (likely to happen sooner) you miss having to use your brain.
Good luck!
Or just work 40/hours a week. That really won't hold you back from having a life.
If you think having a real job is less stressful, you're nuts. Being poor is a bad time. And good luck having a family as an uber driver. You really want to stay in $200/hour software fantasy land.
If you want time set that as your expectation with an employer, negotiate it if you are moving between employers. Most employers are reasonably flexible in the technology world, but of course there are exceptions and some business fields outside tech aren't so amenable so YMMV there. If you can't find an employer willing to work with you, but you are as good as you say, freelance. Hell you can work 2-3 months, take of a couple of months off or get a longer term gig where you work 20-30 hrs a week. Many people have already pointed this out to you.
Employment or freelancing is a contract (even if not written), so If you set expectations up front or negotiate in good faith with an existing employer, you likely can have your cake and eat some of it too. But don't expect anyone to read your mind, you have to be up front.
If you're half as good as you say, freelancing should be a very easy option and provide you with all the flexibility you want. Find companies in need that can provide lots of work and then manage their expectations around your availability.
http://www.mrmoneymustache.com/ http://earlyretirementextreme.com/
Suggest reading up on Alan Weiss, effective proposals> http://www.summitconsulting.com/articles/vol-1-10.php
If you can afford it, you could start a consulting business and work only couple of days a week.
Sometimes i wish i could take all my time off in the form of 3 day weekends every second week.