What are the restrictions ZENworks imaging puts on the way a machine is partitioned?

None. But if you want to restore, and have to do any partitioning (as is already the case if you have a swap partition -see previous answer-), then all tools you have are fdisk, sfdisk and the img program Novell provides. There are a few things I think should be repaired in the img program before it becomes useful[37]:

[37] I may be malinformed, but then the criticism in these lines goes straight back to the makers of the documentation on the program