We don't have Dataforms, but I requested the module be included in our winter upgrade.
I have sort of been using the "Will be graded at a later time" option with rubrics, but have added that comment each time. Renaming the 0 level is a good option. I might use that for the assignment I am doing now.
I didn't know about the Workshop option, although I see it is available to us. I can see opportunities for using it in the future. On the other hand, can I use it without having students evaluation other's work? I haven't had time to test it out yet.
Thanks for your help!