So it sounds like the problem isn't actually storage, but cataloguing and retrieval? This might make more sense as an in-house service somehow, rather than something that involves shipping and the associated costs.
Well, sure, that's the problem, but breaking it down into separate steps that need to be solved should be part of the solution.
I own too much stuff. I would love for there to be a solution more effective and less wasteful than simply throwing it out. I appreciate this post because it's suggesting at least part of a solution...
...although I don't think it would work for me because it requires even more stuff. A working printer (which will inevitably turn into a non-working printer). Label paper. Packing tape. Many boxes of appropriate sizes.
I assume this guy already ships stuff from his house for other reasons, or else all that stuff would be clutter too.