Hacker News Reader

Instapaper did that pretty well, and I think Pocket Premium does that too - in MOBI format, which is much easier to read on the Kindle than PDF.

These days I use Calibre instead because the overall experience is better, but for single articles it's a bit overkill.

I use a script that implements calibre's ebook-convert command line to convert and mail mobi files to myself from html urls. The ebook-convert command is powerful enough that I can join several html pages together, and also add chapter hooks and titles. I used to use this to download and read Wheel of Time rereads on Tor for a while.

I use the Push to Kindle app from FiveFilters.org to do this.

That is a cool idea! Would only require to setup a small server as webhook endpoint that creates the e-mail.