Last November, iTunes began selling M*A*S*H (individual episodes, entire seasons, or the complete series) as a digital download. The episodes on iTunes are available in SD and HD. However, both versions appear to be the same 16:9 widescreen versions also streaming on Hulu.
Around the same time iTunes started offering M*A*S*H, both YouTube and Google Play did as well but I didn’t find out until recently.
The series is only available on YouTube as a “complete boxset” and only in HD. It costs costs $99.99 and is viewable through the YouTube website and mobile app, select Smart TVs, select video game consoles, Android TV, Chromecast, Apple TV, and Roku.
Google Play also offers the complete series for $99.99 as well as individual episodes for $1.99 each or entire seasons for $19.99 each (except for Season 11, which costs $24.99 for some reason). Google Play is available on Android devices (smart phones and tablets) as well as select Smart TVs, Android TV, Chromecast, and Roku.