I just had a thought - and wondered if it was novel, prudent, or even feasible.
Let us say my wife and I do some post-retirement work, like MMM seems to do. For the sake of example, let's limit this to 25000 USD per annum. It appears to me that I could contribute this all to some Solo 401(k)s to eliminate tax on wages, and live off our investment returns which would basically be taxed at 0%.
In addition to skipping out on 500 USD of taxes, it puts more funds into tax-sheltered accounts.
Thoughts?