TeX daemon for Windows

A simple question (in theory): is there any (La)TeX distribution for Windows that is capable of running as a daemon? I am not aware that either MiKTeX or TeX Live are capable as running as daemons on Windows, but are there any other solutions? Failing this, if I wanted to hack an existing TeX distribution to run as a daemon, what would be the best approach?

A few features that the daemon should have, ideally:

• Run as a Windows Service. (optional)
• Callable as a library/API. (optional)
• Input TeX and output DVI/PNG via standard I/O or pipes. (optional)

Any information or suggestions on the subject would be much appreciated.

Edit 1: Specifically, I am also rather curious how the preview-latex package for EMACS works. This seems to have a very similar usage in mind to what I intend.

Edit 2: I've just recalled that the Instant Preview feature of LyX also closely represents what I want to achieve. Additionally, this seems to work on Windows. An explanation/overview of this system and the daemon it uses would be very helpful.

There is William Blum's LaTeXDaemon:

http://william.famille-blum.org/software/latexdaemon/index.html

It's on Google code as well, but I am only allowed one hyperlink.

It will generate a format for the preamble and re-compile every time the document is saved.

• Thanks for the suggestion. I've actually looked at this before and it doesn't seem to be a true TeX daemon. It's mainly a file system watcher from what I can tell. It is also mysterious how it "precompiles" the preamble using only a standard MiKTeX distribution. – Noldorin Aug 5 '10 at 11:45
• In response to your other answer: Cheers, that explains half the story. However, doesn't this LaTeXDaemon still have to relaunch the LaTeX program on each run? Where is the preamble preserved in that case? – Noldorin Aug 5 '10 at 16:13

MathTran runs TeX as a daemon. For macros it runs a secure variant of plain TeX, but with some LaTeX additions, such as \frac. Several years ago it could typeset a single formula in about 10 milliseconds (and so too cheap to be worth caching).

There's an experimental online editor, which gives instant preview (if you have a good internet connection).