Added a Proxxon high-speed spindle to my X3. I went with the 12V version because it's slimmer. I'm not sure if it'll be up to anything particularly heavy, but I hope it'll work for pushing tiny engraving cutters through plastic and aluminum.
We all like machining porn, so here's some video. It shows a lot of setup and such to give a sense to my non-machining friends of all of the steps involved. This is my first project where I've actually made a real fixture and spent some time trying to get my speeds/feeds right rather than just winging it.
[nomedia="http://www.youtube.com/watch?v=tFepQLxqtsI"]YouTube- CNC Milling High Speed Spindle Mount for Sieg X3[/nomedia]
And a blog post with more pictures and text.
Constructive criticism is welcome! I'm pretty new to this stuff, and the more I learn the happier I am.