JproxyOne Saturday I wrote a port-forwarder in Java that does hex/ascii dump logging like an assembly debugger. The model is borrowed from Chris Longo's PlugProxy and the threading examples in Paul Hyde's book. It makes use of GNU's Getopts and Chuck McManus's character encoder.
Released under the GPLv2.
I'm considering adding proxy authentication (Basic & Digest) and an optional Swing GUI to make this really useful.