HOUSTON/NEW YORK, Aug 25 (Reuters) - With Texas one of the few bright spots in the U.S. economy, the skyline of swaggering Houston is where the action is as builders and global oil companies, from Phillips 66 to Exxon Mobil Corp, look past previous busts and spend billions on gleaming new buildings.

The U.S. shale oil and gas revolution - which has already changed industries from railroads to pipelines and refineries - is helping drive the voracious appetite for office space needed for the expanding workforce in the world's energy capital.

Demand is so hot that Houston is one of the few places where banks - including Wells Fargo & Co, which is seen as one of the more conservative big banks - will loan money for a new building without demanding developers first have a tenant.

"Houston is booming and bar none the strongest market in the United States of America," said Joseph Sitt, chief executive of Thor Equities, which has two projects underway in Houston.

There are some 56 office buildings totaling at least 11 million square feet under construction in and around Houston, according to real estate services firm CBRE Group Inc. That is equivalent to 190 football fields.

In the forested suburbs, Exxon has what it calls "one of the largest commercial construction projects underway in North America." The nearly 400-acre campus with 20 buildings will have enough room for 10,000 employees.

With crude now above $100 a barrel, money is flowing freely. And while the shale oil and gas transformation means North America may be energy independent by the end of this decade, economists are wary when people say this boom will be different. They counsel caution.