A couple of months ago I wrote an Inkscape extension that allows users to save LYZ files that are compatible with Laser Draw (LaserDRW). Laser Draw is the software that comes with many of the cheap chinese laser cutters. The Inkscape extension makes it easier for users to get consistently scaled output. This is especially helpful when doing multiple operations on a single work piece (i.e. raster engraving, vector engraving and cutting).
The Inkscape Extension is free and open source (GPL). The extension is available for download on its web page: Laser Draw Inkscape Extension.
On the ScorchWorks YouTube Channel there are a couple of relevant videos. The first video talks about the extension and goes through making a design from scratch in Inkscape.
The second video walks through modifying an existing design for use with the Inkscape extension.