What companies would be a good fit someone who genuinely enjoys software development work and cares about good engineering practices, but doesn't want to do it or think about it every waking moment of the day?

A big, fat company.  Right now I'd suggest Google if you can penetrate.  Some parts of IBM (but not all).  Id guess some corners of Amazon though I don't know for sure. But in general, the bigger a company gets, the less demanding they become of individual employees. Stay away from startups as those all expect your entire life focus.

Your own company building a product of your choosing. Make enough millions you can live off the investment returns, start your own company building something interesting, and have fun making software the right way.  One million might do the trick given very low material needs and/or willingness to move to an emerging country.  Five million is low where costs of living are high, you're hedging against  projected 1.5% real stock market returns with dividends re-invested, Social Security may become means tested, etc. Otherwise your chances are within epsilon of zero to enjoy a reasonable amount of software development, with bounded hours, when you "work  for a company that has interesting development  problems, hires  competent people, and understands the value of good engineering  management." When you require a pay check best case scenarios along time commitment, code/process quality, and opportunity axes to develop software include Hands-on VP of engineering or  technical lead with a VP who delegates process to at a small new company where you  have good engineering practices and interesting new development, although scope and resources dictated by the CEO and investors often mean that's a 70-80 hour per week position  and  too close to "every waking hour" for your tastes. (been there, done that, rank it first over the following options.  When you don't waste too much time commuting that still leaves at least 30 hours a week for other things which can go far if you don't waste it on stuff like TV) Working at most 40 hours a week as a sufficiently senior engineer at a big company with a package totaling over $200K/year making tactical improvements with code and process that could use significant improvement. (been there, done that) Working as much or as little as you want  renting your brain hourly to deal with bad code and process.  There's a lot of cash in telling companies they are loosing money by re-implementing common libraries and that their employees don't remember much from their computer science degree program but those problems aren't interesting development. (been there, done that) Joining a mature engineering organization which got everything right. Such organizations don't have much need for new software development although the little you have opportunity to accomplish can be great in all ways except scope.  I've seen exactly one such organization in decades of work. (been there, done that, learned a lot) All of these are better on at least one axis than other alternatives with the worst being doing little interesting software development,  dealing with bad process, and working a lot.