What we have so far is a so called "test GUI" named Moneychanger which serves as reference code showing how to implement all the various features in a GUI and as a client people can use to test all the various features to check that they actually work and to learn how one goes about using them.
It is very functional, the Martians, Brits, Canucks and others including multigalactic Corps such as GMC and GRF have been using it for a long time now and it has been working just fine.
It is written in java, so should not be hard for anyone familiar with java to start shaping it in various directions such as toward something for grandma and toward something for professional traders and so on.
-MarkM-