Well, everyone here says rumor....I contacted Pontiac directely via e-mail, and got this response:
"Thank you for contacting Pontiac and for your interest in the 2005 Pontiac Bonneville! Production of the Bonneville is scheduled to end in June 2005. Due to decreased demand for full-sized cars, Pontiac will no longer compete in this segment. However, the Pontiac Grand Prix does have comparable interior passenger and cargo space as the full sized models. We appreciate the passion that our customers have for the Bonneville. Pontiac will continue the tradition of providing performance vehicles with high value. To obtain more information regarding the Bonneville, please visit www.pontiac.com
or contact your preferred dealership."
That sounds official to me.