I am also very interested in that matter and I would likely contribute any
help (testing etc ...) if possible.
Ifyou guys plan on rewritimg something clean, I would suggest you consider
using the Java Topology Suite (JTS)
http://www.vividsolutions.com/jts/jtshome.htm as a base for spatial objects,
rather than rewriting them entirely as the previous commiters did.
This would allow smooth integration with GeoTools which is a de-facto
library for geographic operations.
I would also love to see how Wouter's code works and what it exactly does :)
Thanks for reviving this !