Well, I'd like to take this opportunity to point out that a groundswell of users in this area has made this something that will be gaining attention and at least some work to address this year.
First of all, here at linux.conf.au I had a chance to talk with a few guys from Ponoko ( http://www.ponoko.com ). They're very interested in promoting the use of open source to physically make things.
I have been using Inkscape to draw artwork for my homebrew pinball machine project and I am also using it to cut acrylic parts for it. You can see photos, videos and blogposts in these links:
* http://www.flickr.com/photos/felipesanches * http://www.youtube.com/user/felipesanches * http://jucablues.blogspot.com/
I also know that Jeri Ellsworth uses Inkscape to design her pinball stuff:
* http://www.youtube.com/user/jeriellsworth * http://www.fatmanandcircuitgirl.com/live/
Actually, my homebrew pinball project is THE reason why I discovered some years ago the existance of Inkscape (because I was looking for a free software CAD and stumbled upon Inkscape, which is not a CAD tool but got me seduced) and ultimately became an Inkscape developer.
cheers, Felipe Sanches (a.k.a. JucaBlues)