An excellent article - well written and on a very interesting topic.
I also think it's worth thanking Valerie for stopping development. It can be a difficult decision to do so, and takes bravery and good judgement. Chunkfs, especially as a VFS, would likely have become one huge furball of hacks. To accept that it had served its purpose and that time could be better spent elsewhere looks like the right thing.
Now all I have to do is wait for btrfs to bring me all of this. I have resorted to manual mirroring via scheduled rysncs, which balances all the pros and cons nicely for me. I'd never stop doing mirroring in some form, but to be able to trust hardware (or any lower level that includes the fs) mirroring would be nice for fileservers.
So, thanks again Valerie and all involved with chunkfs. Good to know that the future will be better! :-)