I own my own company. I am maxing out my roth 401k with a match of 4%. Can hire my wife and pay her just enough to max out another roth 401k?
I don't know the real answer to your question, but assuming she is homemaker or unemployed, you can open a Spousal IRA for her with the same contribution limits, e.g. $5,500 in 2017. This would be a lot easier than possibly committing tax fraud. I was able to do this for my wife a few years ago with an online investment company.
Legitimate periodicals have written over the years how business owners can shift income to family members. To a spouse to do exactly what you are looking for, and to children, whose earned income is taxed at their rate.
As long as the work is documented and reasonable, e.g. I couldn't pay my 10 year old $50/hr to help file, your approach is sound.