Commercial web RTL has boarded the Hallmark Entertainment fantasy series “Dinotopia” as co-production partner.Shaping up to be one of the most expensive series ever made, the six-part “Dinotopia” begins shooting next week in London. Budget is reportedly $75 million. RTL comes to the project via an existing agreement with Hallmark that calls for the station to co-produce at least three Hallmark productions annually through 2004. RTL has exclusive free TV rights to all Hallmark productions. “Dinotopia” will be broadcast domestically on ABC.