Adelman recently hinted that the Big N was planning on dropping the office space requirement, and it appears that they have done so. In an interview with Gamasutra, Adelman said he "can officially confirm that the office requirement is a thing of the past."
Yes, they [indies or individuals] do need to become licensed Nintendo developers, since they will need access to our development tools. It's actually pretty easy to become a licensed developer. We really have only a few requirements to sign up as a licensed developer with Nintendo. The most notable ones are that you have to have some experience making games, you have to be able to keep any confidential materials like dev kits secure and you have to form a company. None of these should be prohibitive to any indie developer.
...So that second requirement — the ability to keep confidential materials secure — was originally defined in terms of an office that was separate from the home. Back when that rule was created, that seemed to be an appropriate way of defining things.
As you point out, more and more people are working from home, and we recognize that developers are forming virtual teams around the world. I know we've shied away from talking about these things publicly in the past, so I'm glad that I can officially confirm that the office requirement is a thing of the past.
...Anyone from any country can make their games available on the eShop within the NOA and NOE region — i.e., pretty much everywhere outside of Japan.
-Dan Adelman, manager of business development at Nintendo of America
Adelman went on to discuss WiiWare, the eShop's predecessor, and how Nintendo is taking what they learned from the service to make it as easy as possible for indie developers. You can check out the full interview via the source link below.