I know you have tried to delete and re-model the device, but I suspect you did it in the normal fashion. I am guessing that you put it into the same device class as it was before, or attempted to add the device from the drop down..
Here is a possible fix, since it seems to be wedged in the database.
1 delete the device
2 make a new sub-class in the class you want the device in (you can delete it safely later on)
3 go into the zenoss.domain.com:8080/manage portion of zenoss, and pack your database. (this will remove the old stuff)
4 Now go into the new sub-class you have created and add the device via the dropdown menu.
5 Rename the device to ANYTHING other than what it was named before.
6 If RRD data is now being generated, and the OS tab is working correctly, move the device back into the proper class.
7 Remodel the device to pick up any odd template changes that the device might not have gotten.
8 Delete the testing subclass that you created.
Dont know if this will do the trick for you, but when I make a mistake and move a device class that has devices in it, this is one of the ways I fix the problem, since that really breaks installations.
