Sure you can :). Naturally transfers via SSH "suffer" from the encryption overhead but prevent MITM/network sniffing etc. The author points out that (only) in a trusted LAN you could use this solution to make things go faster.
I guess the title should be a little more mild - scp isn't going away, or rsync via SSH for that matter.
It says that it only stores metadata locally not objects themselves (although it could probably have an option for that too and serve as a general S3 cache).
Nice effort, Redis is perfectly fine but I believe that the storage layer should be somehow more separated in case someone wants another type of storage, e.g. in-memory SQLite is adequate and already installed in most systems.
Taking a quick look at the source code directory structure https://github.com/jquery/jquery/tree/master/src, I believe that you could create a minimal, customized build containing only features that you actually want. For example only element selection (which is very convenient and fast IMO) and AJAX.
CSS selectors are much easier to remember than XPath. Python's BeautifulSoup allows you to select elements with selectors and is very convenient. XPath is a bit more verbose and most people already are familiar with CSS syntax.
Nice post! You mentioned that you implemented this wrapper for backups. Apart from creating a virtual file system for sandboxing perhaps, isn't this generally slower? Maybe I am not getting the exact purpose of this task.
Nice analysis. Hope you don't mind me adding that by omitting terms of the Taylor series you do have some loss of precision, however small. Also, solving linear equation systems may even introduce instability as the following must be preserved: http://en.wikipedia.org/wiki/Diagonally_dominant_matrix
I suppose someone could incorporate a procedure which strips down unnecessary strings from code files ("minifies"), especially comment blocks, during the deployment process, thus maintaining a nice development codebase while not having questions over performance.
We also built https://techusearch.com which uses Sphinx indexes (think of a SaaS version of Elasticsearch backed by Sphinx).