Thanks Karsten, thanks Kostas! It's a little disturbing that moria1 is providing truncated responses but guess we'll dig into that more later.
Great points about needing a more flexible downloader. Here's another attempt, this time with a DescriptorDownloader class that's a bit similar to our present DescriptorReader...
https://trac.torproject.org/projects/tor/wiki/doc/stem#RemoteDescriptorFetch...
It still feels a little clunky to me, and I'm not yet sure how best to handle the use case you mentioned concerning votes. Thoughts?
Feel free to edit the page (that's what wikis are there for!). -Damian