I made a similar sqlite vfs in Go[1]. I really love the VFS api. HTTP range queries is about the most mild thing you can do with it. The VFS implementations that use non-traditional backing stores are more fun. Like say, using DynamoDB as a read/write backing store for your sqlite database[2].
That DynamoDB VFS looks cool! I agree that the VFS api makes one think about plenty of crazy ideas. Someone is working on a VFS based on Foundation DB[0] that looks very promising. It was recently discussed here[1]