The Angry Engineer blogs about the disastrous GM Colorado light pickup truck. This will go down as one of the worst business decisions in the business: spend a billion dollars to develop a vehicle for a shrinking market segment (the compact pickup), and screw it up in the process.
Sorry to sound so negative on so many things (such as the Zephyr), but the Hummer H3 sounds like another disaster about to happen.
The Hummer H3 is going to be built on the Colorado platform, much the same way that the H2 is built on GM's large truck platform. So it is going to be a large, 2-ton brick, about the size of a Ford Explorer, with the less than exciting (ask Car and Driver) 220HP I-5 engine. An Explorer, BTW, can be had with a 4.6L V8; a Jeep Grand Cherokee can have a 4.7L V8. GM's answer: "It will have good fuel economy". Oh, and it will cost about $30,000.
People don't buy Hummers for fuel economy, they buy them to make a statement (of poor taste).