I'm not crazy! I just confirmed it!
I tried to convert one of my blocks to furniture and it gave me the "you have too much furniture" message (which is what I would normally have expected). Then, without adding or removing any furniture from my inventory, I went to buy a box, and it was successfully purchased and added to my inventory. Which PROVES that the cap WAS increased, but was not adjusted for the "Strange Brick" loot-furniture conversion.
I KNEW something had changed. 4-Lom, I hereby request to be discharged from the asylum.
Edit - I went back and counted the furniture in my inventory. I had 56 pieces of furniture, and was able to purchase a box. Anyone who has as much furniture as I do knows that normally you'd have to dump a bunch of furniture and bring that number down to like 20 in order to purchase anything without getting the "you have too much furniture" message.