Thanks to jefexp for the heads up
On the 23rd of April 2004 Microsoft accidently granted a few beta testers access to various builds that are normally reserved for OEM testers. We can confirm that the build released bears the tag of 6.00.2900.2111 (xpsp.040409-1745).
Other builds that a select few testers were given access to were 2064/2082/2090/2108 and 2077. Microsoft were unavailable for comment regarding the slip up. So far we"ve not been able to establish anything new with 2111 but we"re expecting RC2 to be released on May 12th with the RTM on June 23rd. Current internal builds are at 2117.