EPS10 supports transparency and layers in vector graphics. Can matplotlib generate EPS10 files?
I am fairly sure that matplotlib cannot do this. Indeed, I do not think that EPS10 is a specified version of EPS, but rather than it is just a tag to denote .eps files saved by Adobe illustrator version 10 (or above) with the "Illustator 10 EPS" option. This forum thread seems to support that view.
I can't find a canonical reference on the Adobe site as I'd like, but this blog / article does a good job of explaining what it does and the fact that it is an option on saving EPS in later Illustrator versions.
As a side note - it looks like the format is obsolete in the most modern versions of Illustrator (see forum question here)