They stopped with the Retina MacBook Pros. I think it's still doable in the base non-Retina.
By the time I need upgrades, I also need a new screen and keyboard though.

I've only had a 2006 MacBook Pro and a 2011 MacBook Pro.
But yeah, I will probably move towards the Mac Mini because I need the ability to upgrade stuff. Heck, I still need a HDD over a SSD. It's getting really complicated! Probably will have to live with my clamshell mode setup for another year.