I think storj is worth mentioning. You could also look at the list of supported providers for rclone.

Before vitamin D can be stored in fat it must first be absorbed from the digestive system into the bloodstream. The absorbtion efficiency varies by individual but no one absorbs 100%. After making it into the blood some excess vitamin D can be stored in fat cells for later use.

That is a perfectly reasonable amount of vitamin D to take weekly. If taken orally not all of it will be absorbed anyway.