I’ve been searching for a Web-based SSH for quite a while, and I recently read about GateOne on the dedicated Wikipedia page. Not only GateOne does what I was searching for, but it also comes up with nice features like interpreting images on-the-fly.
The remote server on which I intended to run this software is, of course, a NetBSD 6.0 domU, and as I anticipated, some work was needed in order to make GateOne work on this platform.