The gas-turbine/electric had 60-100 MPG range.
The Diesel/electric had a stated 80 MPG.

Of course, if you used them in shorter commutes and could charge them instead of using gas (or diesel fuel), you could get much higher mileage than that.
If GM had only just kept up their R&D on these fronts, they would have a monster product of some sort IN THE MARKET by now (instead of playing politics and catch-up). I'm still very hopeful for the Volt and Saturn to hit the market in time to be smashing sucesses. And, GM needs them to.

Steve

STOP terrorism - Drive a HYBRID

Vehicles:
350 miles a week ------------ 2006 HCH II, Magnetic Pearl, w/NAVI (born on May 25, 2006)
350 miles a month ---------- 2003 Mazda Tribute ES-V6
350 miles a year (for now) - 1986 Mercedes 560SL