I think more to the meat of the question
to paraphrase "Is there any way to get
more than my initial 50 allotments of Mog Safe Space?"
Yes there is, but it isn't through the purchasing of Items like you might think. I remember buying a "Chest" for 2K thinking "Cool . . maybe I can get 3 or 5 more Safe Slots." only to be dissapointed.
Standard items (Tables, stools, Flowerpots, etc) take up one space in the "Mog Safe". These items then give you one slot of "Storage" space that can only be accessed from your home town. This "Storage" space is only to make up for the fact that the items takes up a slot in your "Mog Safe".
There are some special quests I have heard of in passing where you can get "Beds" to increase your Mog Safe space by 10, 20, or even 30 slots. I also read in passing that these quests take mucho time, and Gill.
As for me . . I keep my plants on the table, and chest I bought in error, and chalk it up to experience. I have been too busy crafting to investigate the potential of mog safe expansion . . . though it
would be nice for the power crafting sessions
also There are
Gobbie Bag quests to increase your carrying capacity by 5, 10, and 15 slots. I have done a little more research into these, and it costs around 25-35K for the 5 slot quest if you buy all the stuff. Pluss you need good Fame in Jeuno.
Now If someone were truly kind, and knew which quests gave the mog safe expansions they could take a few minutes, and post the links here to edjumakate us ignerant peeps.