Yup, the IBM Design Language is a growing library/guidelines for all new IBM Designed products. Still a work in progress, but there is finally a unified look/feel/function for future apps/sites.
I'm a recent hire at IBM Design and leading a design team.
nfriendly, your experience is what it's like working with a non-IBM Design team. The old way is to have a single designer on something and that person has little to no authority to be the users through the design process. That's all changing now.
From my understanding, there have only been a couple of hundred products (in the 3 years since IBM Design was created) that have been updated using IBM Design Thinking. There is actually a dedicated design team (min 5 designers) working on each product that is getting attention at that moment in time.
But there are over 5000 products that IBM sells, so it's going to take a while to get to them all (also assuming some of these will be consolidated as the design cycles address the user's needs). There will be a lot of time that passes before all the engineers at IBM (with it's 400K+ employees) get to have a dedicated design team on their product.
Having been a number of startups and advertising agencies before this, the "design culture" is strong here with a lot of smart folks fighting to turn around a very very big ship.