Oh Molly, I feel for you and Daisy!!! She's one of the big danes right? Poor girl!! They were going to do a barium series on Duncan if he didnt' stop vomiting also. But he did after a few hours luckily....The vet couldnt' see any blockage on the xrays? They sent Duncan's xrays to an actual people radiologist to be read because the vet was unable to see a blockage and wanted to be absolutely sure....You said it was an alternate vet? Is your vet out of town? Is this a major vet hospital where you could get a second opinion before you and Daisy have to go through all that?
My vet also suggested a Pepcid table to calm the stomach and a tablespoon of food to see if it stays down at all...If not, problem, if it does, not so big of a problem...
I'm sure you've been through all this Molly but I jsut wanted to reiterate some of my experience in case.....

Good Luck to you and Daisy. I hope she will be ok and soon!!