Every building I've seen at Microsoft is big enough, although some are (or are being switched to) open-plan.
Now that I think about it, everywhere I've worked there was enough space so that everybody working there at the time could have had an office.
As to where I'm going to find them: I'm probably going to filter out employers that can't make enough money with programmers to afford an office for each of them. I know this removes a non-trivial number of employers from my potential field of employment options.
The Symantec (formerly Central Point) offices in Beaverton, Oregon, for one. It's been years since I've seen the inside of it, but at least into the early 00s, even low-seniority QA guys had private offices.
Things are relatively cheap when you don't try to locate them right in the middle of an overcrowded city.
I've worked in places with 30+ programmers - what building exists that a company could afford to have 30 private offices??