Ok, so I did a TON of research and fiddling around, I think what I may be able to do is the following:
1. Split the polyline into individual line segments.
2. Also convert the polyline into a point file.
3. take the first two line segments and create a buffer around them
4. take the first 3 points and create thiessen polygons from them
5. clip the thiessen polygons using the buffer created in 3.
6. add the thiessen polygon containing the first point into a new shapefile
7. repeat, on the 2nd and 3rd line segments and the 2nd-4th points, etc etc....
This will end up with the original buffer split into sections corresponding to each vertex. The iterative method (only looking at 3 points at a time) will mean that it will create polygons that can overlap, as long as they're at least two points distant.
The only issue I see now is when the animal doubles back on itself right away, I won't catch it until the 2nd waypoint of overlap, But hopefully that will be a minimal problem.
Does this sound feasible or have I been thinking about this for too long and missed something? 🙂
Thanks so much for your suggestions, I never would have come up with this on my own.
Adam