LIFE CYCLE ANALYSIS FOR PHEVs?

Does anyone know if some work has been done on a life cycle (i.e. cradle-to-grave) analysis of PHEVs’ environmental impact versus conventional gasoline-powered cars of equivalent sizes?

I’m particularly interested in the Chevy Volt, but information on other PHEVs would also be welcome.

Even if you don’t know of such an analysis, but are aware of academics or institutions working in this field that might have done such work, then I’d be grateful for leads.

Thanks,

Peter Hunt