Please correct me if any assumptions below are incorrect.
Only two 19 x 13 x 11 milk crates can fit in the basement:also
However, one 19 x 13 x 11 and two 13 x 13 x 11 can also fit:
If you have the optional interior access installed, there is a problem. The access is 4" from the floor and just 7.5" tall, making the top edge 11.5" from the floor.
But the crates are 11" high, thus making it impossible to access the contents of the milk crate. the crate/container should be at most be 6" high to make the contents accessible from the inside.
To address these issues, I've been playing around with some custom designed containers as shown below. They can be constructed using fiberglass over molds. OTT has the expertise to do this easily, but the production team have their hands full producing TTs and probably won't be interested. A local fiberglass shop is willing to do it ($$). Another way is to use 0.25" polycarbonate and poycarbonate cement to construct them ($$$$). Yet a third way would be to use wood ($?).
All the containers are 12" high (leaving room for casters underneath). Container 5 has a lip of 4" in the front And a height of 12" in the back , for those who have the interior access installed. Otherwise all sides should be 12",
Containers 4, 5 & 6 are restricted to a 14" length so that they can easily "turn the corner" when sliding the in or out: