This is a quick reminder for Inkscape developers that OpenRaster
project has been evolving  thanks to Cyrille Berger of Krita team
and =D8yvind Kol=E5s of GEGL/GIMP teams for quite a while now. The project
was mentioned in this list early in March this year. I've just checked
again and it turned out that it wasn't really much discussed.
Here is a short overview. OpenRaster aims to become an OpenDocument
format (ODR) for multilayered raster graphics with clipping paths,
masks, layer effects etc.. It is going to become a standard for
exchanging of project data between users of different applications.
Repesentatives of several opensource projects have expressed their
interest in supporting this file format by providing either exporting
or importing (or both) filters for it, when this standard is approved
by respective OASIS TC as such (or even earlier). Krita/SVN and
GEGL/CVS HEAD already have initial supporting code. There is a draft
document from June 2006 available  to read.
In case of Inkscape this task might be quite simple, since it can
already write OpenDocument Draw documents, and exporting an Inkscape
SVG document to ODR, when ODR is ready, would be a matter of exporting
each layer to a respective PNG file and combining them into ODR
layers, with clipping paths or masks where applicable (some effects
like Gaussian blur could be exported to an effect layer, too, possibly
by means of XSLT), then saving it to a ZIP archive (sure, I
oversimplify this description :)).
If any of Inkscape developers is interested in supporting this file
format in the future (especially since it is going to have basic
vector graphics capabilities) -- at least exporting to it, the team
would appreciate your input. Most discussions are held in CREATE
mailing list .