I feel like I have seen an answer to this before but I just can't figure out where I may have seen it. Or perhaps I'm going insane and that was my alternate reality I dreamt all this up in. Searched the admin guide, thwack, and the success center and so far all I've dug up is this: Set up the storage location and firmware repository. I have some (well.. maybe some is an understatement) Dell switches that use .stk firmware file extensions. I'm going to take a crack at making a firmware upgrade template for them.
Thanks in advance folks!