Not open source need a plurasight membership but I thought this course pretty far along on the "well-engineered" architecture(if it's the one I was thinking of).
Thanks, I'll definitely check it out. I found mvcforum to be surprisingly well built (https://github.com/YodasMyDad/mvcforum) but even there you could see major changes had to be made at some point (like completely dropping the repository layer in release 1.8).