I finally got a direct dial number to the US Customs office and bypassed the UPS Customs Brokerage. Inspector Hillman was more than happy to help me track down the DMS50s and find out why they'd been sitting idle in the warehouse. After verifying all of my information, getting values on the packages and running through the standard script of questions he started digging. Turns out the package was held for a random check but, since no one noted what they were checking for, the package was never actually put in the queue to be checked.

Inspector Hillman said that the package would be processed today or Monday and would definitely be on the truck on Monday. I won't naively blindly believe him but at least I'm now talking directly to a customs agent instead of the customer service representatives at UPS who are looking at the same Web page that I am to get status on a shipment. Regardless, looks like we'll find out on Monday.