I got my bits from Ponoko the other day, and have been trying to figure out why all my parts were scaled up by an unknown value.
At first I thought I modelled my bits wrong, then I though it might be a problem with Skeinforge.
Now after several hours I think that the Ponoko template is somehow scaling stuff up.

I created a simple 10mm cube and copy pasted a layer into another document, and printed it out with a regular printer, as this is what I found to be the actual size of what is laser cut.
when I paste the same layer into the Ponoko template, it gets scaled up, and i've gone though InkScape up ad down, I can't see why it would do that.
Anybody got a clue?

Nope, had the same thing. However, somebody from Ponoko contacted me (I left the orange safety area border in) and noted that the scaling was wrong. However, given they they provide the templates, I think they should ensure they have been tested with Inkscape to give properly scaled output. I have no idea what's going on here.

In the email conversation I did get the idea that they themselves mostly work with Illustrator.

-Geert