In terms of provenance research of their holdings, German museums historically have always been one step ahead. The Museum Fünf Kontinente in Munich leads by example again, by making scans of the original inventory books of its ethnological collections available on their website. You can find them here (in chronological order on the left of the page). Funded by the Bavarian State Ministry for Science and Art, the museum with this projects wishes to make these important historical sources freely available to researchers who wish to study the museum’s collecting activities and acquisitions.
ps thanks Ingo Barlovic for the tip!