How would I track when a file's contents have changed remotely?
I've seen the "rev" value, but this also increments when the file is moved/renamed, and I'd like to ignore any changes not related to the content changing.
The rev is currently the best way to track changes like this. If the rev hasn't changed, you know that the file contents have changed. If the rev has changed, the file contents may have changed.
The rev does change when a file is moved or renamed though, as you mentioned. It sounds like you'd be better suited by a hash of the file contents. The Dropbox API doesn't currently offer files hashes like this, but I'll be sure to pass this along as a feature request.