I have a potential use case where it might be useful to read/write OpenVX graphs to some file format (say xml).

This is to allow offline processing which could be used to generate custom architectures for specific graphs.

Has such a case been considered, or would you expect vendors to provide their own API's?

Here's a bit more detail on what I was thinking;

* Develop OpenVX application on a PC
* Save graph after testing
* Run through a compiler tool chain to produce a custom hardware design
* Run hardware on embedded platform, potentially re-loading graph to derive interfaces