I asked them when the Yaris D4D might be available in the U.S. Their response I've posted below.
Thank you for contacting Toyota Motor Sales, U.S.A., Inc.
We appreciate your interest in Toyota products.
We apologize; we do not currently have any announced plans to introduce a diesel-powered Yaris in the United States. We are, however, aware of consumer interest in this type of vehicle and have documented your comments at our National Headquarters under file #00000000000000 .
Toyota is committed to hybrid technology. Though diesel powered engines do deliver comparable MPG ratings to hybrid vehicles, they do no bolster the environmental benefit that gasoline-electric hybrids do.
We invite you to visit our Environmental Technologies and Hybrid Technology Availability for Other Toyotas FAQ?s (Frequently Asked Questions) to review more detailed information on these topics.
We thank you for your enthusiasm about our products and hope that you will continue to consider Toyota for your driving needs.
If we can be of further assistance, please feel free to contact us.
Stan Peters Toyota Customer Experience