Traverse client focus across tags

[doa379]

Is there a way to traverse focus of clients across tags? Sort of like 
cycle_all +- 1. However I would like the scope of clients to not just be 
limited to the current tag.

Alternatively, how can I determine if a frame is the last or only frame 
on a tag? That way I can use a wrapper for cycle_all to intercept the 
last client on the tag and move to the next tag.

I would appreciate any suggestions.