Predicting the landing site of a saccade while the saccade is still in progress A brief look through the literature didn't reveal any algorithms that have been directly applied to the online prediction of saccade landing sites while a saccade is in progress.

While there would surely be considerable noise in any such estimate, the direction vector, velocity and acceleration profiles should contain sufficient information to make a reasonable guess. Is anyone aware of any papers which have attempted such an approach?

Also, how good an estimate of landing site could be derived, and how early prior to landing could this estimate be made. What methods would be suggested for making such an estimate?
Interesting question! Trying to interpret your question, I think what you are after is a model that can predict the saccade endpoint based on eye tracking data? 

The following answer is more of a basic neuroscientific approach:

The neuronal responses (spike rates) in the superior colliculus (SC) can be accurately used to predict the total saccade as a vector. Basically, when you model the response properties of all the SC neurons involved in a saccade, one can calculate the vector sum of all these different neurons. With this vector sum the saccade can be totally described in terms of its direction and amplitude. With the vector sum, hence, the end point can be predicted. 

If this subject is of interest to you, the early work of Van Gisbergen and John van Opstal (based in Nijmegen, the Netherlands) are a good source.

Reference:
Van Gisbergen et al., 1987