It looks like Nintendo’s come out with an answer on worldwide storefronts. From http://kotaku.com/nintendo-answers-and-avoids-our-switch-questions-1791402953:
The Nintendo Switch system is not region locked, but we recommend that players buy games within their region to ensure full service and support. The user will access the Nintendo eShop that corresponds to the country identified in their Nintendo Account. (Up to eight user accounts can be created on a single Nintendo Switch system.)
So, locked per-account, but you can use another account on the same system if you really want something from a different region. Not optimal, but I’ll take it.