(Reuters) - Cadillac's new boss believes General Motors' premium brand could eventually sell ultra-luxury cars that retail for a quarter-million dollars by 2029.

"It is too early today for a $250,000 Cadillac," said Johann de Nysschen, in an interview on Wednesday at the annual auto show here. "Fifteen years from now, it won't be."

Cadillac's current flagship car, the XTS sedan, tops out at around $70,000 which is tens of thousands of dollars less than the range-topping models of such German competitors as BMW and Daimler AG's Mercedes-Benz.

De Nysschen, a former import executive who was named Cadillac president in August, is overseeing a product blitz that will cost GM an estimated $2.5 billion over the next six years, he told Reuters.

As part of that brand overhaul, Cadillac is readying the launch next year of a new high-end sedan, the CT-6, followed by an even larger, more expensive model by 2020.

De Nysschen hinted the CT-6 will be priced "in the 70s," or just above the XTS.

He also said Cadillac is looking at a smaller model positioned below the ATS, one that might compete with the Mercedes-Benz CLA.

"We quite clearly have in the passenger car line an opportunity below where ATS is positioned today," de Nysschen said. "There is a whole new category for compact premium sedans."

Cadillac may also get more crossover models to supplement the SRX, he said.

"The Germans have so many you can't keep track. An obvious, obvious shortcoming in our lineup."

(Reporting by Nichola Groom in Los Angeles; Writing by Paul Lienert in Detroit; Editing byBernard Orr)