Is anyone interested in collaborating on solution-level schema for describing workflow solutions?

I'm particularly interested in capturing the complete description of a StateMachine workflow ...including the layout, etc.

I'm imagining a fairly straight forward schema would capture all of the layout information in addition to the collection of activities and their relationships.

<solution>
<projects>
<project>
<workflows>
<workflow>
<activities>
<activity> ... </actvity>
<activity> ... </actvity>
..., etc.