We (Roger Kapsi & I) would like to contribute a Patricia tree. The tree implements the Map & SortedMap interface, meaning it can be used as a replacement for any arbitrary map. It also implementes a new 'Trie' interface, allowing other implementations or other varieties of Tries to be added. The tree is currently written for generics, but that can easily be removed. We have used the tree as the structure backing a route table in a new Kademlia-based DHT, as the structure backing an IP filter (storing IP addresses & IP ranges, allowing retrieval/searching in nanoseconds), and have tested it with Strings by storing all of 'hamlet' and comparing it against a TreeSet. The tree is also ready to implement NavigableMap whenever Java 1.6 becomes available.
I will attach the files in an update to this issue