http://www.greygreen.org/tmp/dsc_8069.jpg
is a not very good photograph of a poster I worked on recently that was printed by a commercial printer. It's 85x200 cm (33.5 x 78.7 inches).
It was printed from a 50MB pdf sent to a commercial printer. The printing of the vector elements (text etc.) is sharp - that's not obvious in this snapshot.
I used Inkscape 0.46 and a reasonably recent cairo. I had to manually convert blurs to bitmaps, and clipping didn't seem to work in cairo pdf output, so I had to actually crop the images or use PNG transparency (all Gimp work). These were relatively minor irritations, I assume cairo will get these things sorted eventually.
The printer didn't report any issues with the PDF, the printout is exactly how it appeared in Adobe Acrobat Reader.
Hardware wise it's a plastic material that rolls up into the silver base like a roller-blind. The pole that supports it from behind folds in three like a tent-pole and also stores in the base. I'd assume it's moisture resistant, but not good in windy areas.
Working with the shadows made me think an extension which creates a layer of shadows for all the objects in the current layer would be nice.
Cheers -Terry