Yes, the factory has done this to dealers in the past on tandems, their Moto FR-T suspension tandem forks, and other tandem-related items or new offerings, e.g., '00 MT4000 with dual-disc brakes that never was. If there was a run on the initial '04 production run of tandems (which could be the case), then they are probably in a back-order situation. Moreover, Tandems are not a major part of the C'dale line and always take a back seat to other, higher production priorities and larger backorders. Thus, your LBS is probably just as frustrated as you are at this point and there's nothing they can do about it.
You might want to check with Mel Kornbluh at Tandems East in South Jersey (www.tandemseast.com
) to see if he has an RT1000 in your size in stock OR one of the other tandem speciality dealers who sell Cannondale Tandems, e.g., Tandems Limited, Mt. Airy Cyclery, etc... A list of tandem dealers with links to their Web sites can be found on our "Tandems" page: http://www.TheTandemLink.com
FWIW: Burley, Co-Motion and the other tandem speciality dealers have stock models available on the shelf throughout the year and are flexible enough to turn new stock build or custom orders around in 4 - 6 weeks or less. That's one of the benefits of dealing with a speciality tandem producer.