You can't talk about a "limit" the same way we talk about "limits" i.e in athletics ("what is the time limit of running the 100m?").
The reason is simple, and its that beside human and gear"limits" (and evolution), there is an ever changing uncontrollable variable that is nature: mostly wind, but also water conditions, etc.
Maybe you hit a gust, maybe not, maybe strong gust, maybe weak, maybe thermal, maybe a giant wave, maybe a gust right at the tip of the giant wave, etc etc etc. there are people who "jumped" to the sky just due to lofting while on beach.
To talk about limits makes sense only within a given set of specific conditions, like, what's the limit in flat water, 30kn steady, etc.
This is all theory obviously, I think that in a sport like kiting what really counts is overcoming own personal limits and fears, and that's why it's so awesome, you can feel like an hero even if your performing 70% worse than the best. At least that's what I tell myself after spending hours trying to get past an absymal 10m...
And yes...you have to land it