Schema style and parser performance

We have all seen the various styles of WXS schema in use: Russian
Doll, with everything nested, Venetian Blind, full of global complex
type definitions, and Salami Slice, with global element definitions
accessed using "ref" attributes.

Has anyone considered the effect of these different models on parser
performance, either from a theoretical or practical view?

I am considering whether it is worth writing a stylesheet to convert a
venetian blind design to a russian doll model as application
performance is critical.

Regards

Paul Spencer