Thank you Alexander for this analysis. I just read the full docs for the cycle tag, and despite I have used it in the past, I was not aware of its complexity!
My first reaction was that any extension to this template tag would be quite cumbersome, and then after reading the ticket, it seems that Malcomm in comment 3 and Alex in comment 14 also thought that the implementation could get tricky and lead to confusing and/or ambiguous syntax.
Based on the above, and taking as a precedent other template tags that offer their seq version (escapeseq, safeseq), I think we could consider prodiving a new cycleseq tag. This way we could start fresh with a clean and polished semantic for this tag.
What do you all think?