Folks, I can't believe it myself, but this day has finally come - Google seems to have finally sorted out all its backend and frontend issues with Google contact sync. Jelly Bean's 720x720 hi-res contact support was surely a nice addition, but ended up almost completely useless in our earlier tests: Jelly Bean Bumps Contact Photos To Hi-Res 720x720 But Google Sync Continues To Clobber It With Low-Res Mush.
As of today, all the problems I ran into before have been resolved. Removing and re-adding an account now syncs the contact photos in full resolution. Moreover, and much more importantly, Gmail on the web now has a brand new UI that finally supports setting hi-res contacts straight from the browser. I can't even begin to describe how long overdue this is, so for the past 35 minutes I've been doing victory dances around the desk instead of writing the post.